Adhesive for Refrigeration Panels

[exMaggieDrum]

Cheechako - thanks for the offer. I have plenty and I am thinking of using it still. It will be completely sealed on one side with epoxy so I don't think water penetration should be a problem. I never had a problem with the smell on my other boat. It was durable and easy to clean. And I used 5200 and made nice clean applications.

I am still thinking of clear coating the stuff with some food-grade food-grade epoxy although I may talk myself out of that.

ColdEhMarine - wow! That website is definitely stream of conscious style. Pretty eccentric, but often you get the best stuff from guys like that. He sells the LiquaTile 1122 for $195 for 3 quarts. Not cheap stuff. I'll call and ask them about it tomorrow.

One think I can tell you all - this has turned out to be a very expensive project!!! (even in comparison to some other boat projects) I don't even plan on adding up the receipts, which I don't do on most projects. Too scary and depressing.

[Typhoon]

Glad to be of help.

We should never add up the bills when we do boat projects , way to scary.

I'm presently in the middle of building a hard cockpit Bimini of fiberglass with a nice teak rail around it . I don't want to know what I have into it so far , and I'm only half way.

Regards John.

[skipmac]

Third vote for not adding all the costs. Not only is it scary and depressing for me but I would be terrified my wife would find it and learn exactly how much I'm spending on the boats (yes plural).

[duefocena]

Originally Posted by exMaggieDrum

My complete redo of my refrigeration boxes is one of the hardest projects I have done. It is getting along though and I am at a crossroads and rethinking how best to bond the interior panel skins at the right angle corners inside the freezer and reefer boxes. It will be a cold plate/spillover type system.

I had to completely remove all the old interior - open cell foam insulation and old painted plywood panels. It had too much "framing" on the inside under the panels so I removed most of that as well. I have had to rebuild with some new framing to screw down new panels. The gelcoat "paint" had cracked in the old corners and moisture got behind the panels which caused mildew and rot and the wet insulation was failing.

I got some "structural" pre-made 1/4" FRP panels from McMaster-Carr to line the interior but they are raw FRP on both sides and I did not want to put paint on top of them which would eventually flake off. So I also got some thin FRP panel from Home Depot which is white and shiny/bumpy on one side and smooth on the other. I intend to install the structural panels with flat-head screws to the framing over the new insulation.

Then I will epoxy the thin panels on top of the structural panels over the screws. The idea is to completely seal the interior so water/moisture cannot get in to the insulation (a mix of Cryogel Z and rigid extruded foam board anywhere new screws might go - e.g. cold plate holders). The Cryogel Z is another story for later. It has been somewhat of a nightmare from a mess point of view.

My idea to seal all the corners was to put in epoxy fillets at the right angles where the interior white/shiny FRP panels would meet. These will be fairly close tolerance so the gaps will not be large. The epoxy should bond well to the sanded/clean FRP panels. I was not going to put in fillets for the structural panels corners before I glued on the thin shiny panels. Once the white thin panels are epoxied to the structural panels the two become structural as well. This should be a strong box construction.

Smooth epoxy fillets would be durable, strong, and easy to clean although they would not be white (pigment will make them less strong and it doesn't work very well anyway). I don't mind the color but sealing and cleaning are very important.

Now I am wondering if the natural flex inside a boat will end up cracking the fillets. The panels will be screwed down to the boat interior structure but that will flex some any way. There will also be pretty extreme thermal changes which might cause contraction/expansion of the panels, e.g. bringing the interior down to freezing levels and then dethawing many times.

So I think some kind of flexible bonding would be called for if, in fact, the fillets would crack and fail. Then moisture would get in the insulation and that is a problem. The panels will be plenty strong without the fillets but the corners might not remain sealed. On another box I built, I glued on the same smooth FRP panels on top of rigid foam board. I used either 5200 or 4200 (can't remember from 15 years ago). It worked but repeated cleaning of it seemed to make it want to peel and it was harder to get "dirt" off of the softer surface.

I think the answer is No but would the epoxy fillets be flexible enough to handle the expansion/contraction and flexing? Are there other products to provide a strong bond that is durable, flexible, and easy to clean? I am now thinking that I will need to use one of the tried and true adhesives/caulks like 5200 to seal these corners. This is a permanent installation so removal of the adhesive caulk is not a concern. Any ideas?

Tore out my sea frost engine driven and installed technautics 10 years ago.
Added foam from Home Depot inside and covered inside foam with PVC sheet rubber cement glued to foam. Heated with hair dryer the sheet material and "bent" corners to prevent caulking corners. Carried PVC sheet 2"-3" past corners and glued to overlap sheet with PVC glue.
10years no moisture, frozen ice cream, hardly needs to run.

[Delancey]

Given that the FRP panel in question is one of the few finishes other than ceramic tile that is approved for commecrial kitchen applications, I am surprised to hear concerns about off-gassing or toxicity.

If you have ever eaten in a restaurant in the US you have surely eaten food, including fresh produce, stored in a walk-in refrigerator lined with this stuff. Likewise for anyone who eats meat since this stuff is used virtually in every meat processing plant / butcher shop / dairy operation throughout the country.

In my own personal experience I found it to be thoroughly satisfactory for the purpose proposed. Keep in mind also that almost all production boats have coolers made from gelcoat-lined molded FRP pans.

Maybe I am wrong about the potential hazards involved but the ubiquity of it’s usage makes me think not. Some people also think vaccines against polio are hazardous too so who knows.

In my case I vacuum bag laminated the FRP sheets to marine ply with epoxy then used epoxy fillets (unpigmented) in the corners. Here is a picture pre-fillets. The temp screws used for assembly were removed after and filled with thickened epoxy and the whole exterior coated over with several coats.

No worry about failure of the fillets if they are sized appropriately and use a structural filler. A very solid construction technique integral to cold-molded and stitch-and-glue boatbuilding.

I think Terra Nova’s approach is a good one, but in the end it is a paint finish as opposed to a pre-finished material and is more work and maybe not quite as durable since it is only a paint finish thickness.

[Delancey]

Here is a shot just after I did the fillets but before I removed the masking. I would not skip the masking given the bumpy texture of the FRP sheet and a desire for a neat appearance.

Filleting is a messy job no matter how careful you are and the masking provides nice straight edges on the bumpy surface while keeping clean up to a minimum.

Yes the color of the unpigmented epoxy was off compared to the white color of the sheet but I could live with that, sloppy looking fillets I could not. I used high density filler, which is marble dust, and the color was sort of a whitish yellow.

I will say it was easy to clean and served us well for three years of daily liveaboard use until we lost the boat. I never smelled bad smells and the beer was always cold!

[Bill O]

Originally Posted by Delancey

Given that the FRP panel in question is one of the few finishes other than ceramic tile that is approved for commecrial kitchen applications, I am surprised to hear concerns about off-gassing or toxicity.

Styrene is the main monomer used to make FRP panels, is a volatile compound and can be toxic with chronic (long term) exposure. Not that you'd be exposed like these people 0233 Long-term styrene exposure impairs colour vision in fibreglass reinforced plastics laminators | Occupational & Environmental Medicine

The "sweet smell" when you cut FRP panels is the styrene coming off. Personally I can smell it well after the panels have been cut and up for a while. Again I wouldn't want it enclosed with my food and want to avoid the extra exposure by eating it (now absorbed in your food), but that's just me.

Life is too short, why chance it?

[john61ct]

Originally Posted by ColdEh Marine

Of course food grade
POTABLE WATER Epoxy Paint 603.435.7199

For cheap and "good enough", where the boat costs less than some of these high end refrigeration systems,

assume a strong outer shell, then layers of rigid foam securely glued, so no flex or movement.

What would you think of this stuff just painted on, thickly and/or several coats, and call it done?

If not, what additional layer would be needed in between?

[Delancey]

Originally Posted by Bill O

Again I wouldn't want it enclosed with my food and want to avoid the extra exposure by eating it (now absorbed in your food), but that's just me.

All the power to you. Are you also vegan? Grow your own food? I see you have what appears to be a ferrocement boat. I think that's great. Most of us dumb schmucks here actually live INSIDE of FRP boats.

You remind me of my friend's wife who is from Sweden. She complains all the time about America and how wrong everything is here. She didn't like it when I served here some lobsters I grilled on a propane grill once. She also doesn't like it that Americans wrap their cheese in plastic. I kinda think she's funny.

Meanwhile, FRP sheet is literally all over the place where saniitary hygiene is mandated by law in the US. Glad to know you are staying safe by avoiding all of the places included in this short list of it's uses.


Breweries
Cafeterias
Clean Rooms
Cold Storage
Dairies
Fisheries
Fast Food Chains
Food Processors
Hospitals
Kitchens
Nursing Homes
Pharmaceutical Labs
Restaurants
Supermarkets

I am curious though, just exactly what it your cooler made out of? Or do you not have a cooler? That's cool too. Although, I will say refrigeration has done a lot for humanity.

Stainless steel might make a safe alternative for people like you who are very concerned about this sort of thing. Probably the best option out there but man, custom fabricated SS liner for a boat cooler? $$$$! Not on my budget.

[Cheechako]

The pebble texture panels I have have no evidence of glass fiber in them. ...? But I guess they are. They seem more like ABS plastic or something....
Fiberglass Reinforced Plastic
Especially suited for commercial bathrooms, 100% waterproof
Does not support mold, mildew or bacterial growth
Chemically inert and UV resistant, Color goes all the way through
Smooth "pebble" surface cleans up easily, even ink markers
Moulding pieces also available for neat, tight installations
Can be glued in place with waterproof panel adhesive

[Delancey]

Originally Posted by Cheechako

Fiberglass Reinforced Plastic
Especially suited for commercial bathrooms, 100% waterproof
Does not support mold, mildew or bacterial growth
Chemically inert and UV resistant, Color goes all the way through
Smooth "pebble" surface cleans up easily, even ink markers
Moulding pieces also available for neat, tight installations
Can be glued in place with waterproof panel adhesive

Yeah, see this here? These qualities including chemical inertness combined with lower cost than ceramic tile or stainless steel installations are why pretty much all the food Americans eat is either stored in or passes through a facility that uses this material as an interior finish.

Life is short, why chance it on mold, mildew, or bacterial growth contaminating your food?

[Bill O]

Wow, Delancey you need to lighten up a bit. Just trying to inform people of the facts. What one does with that information after that is an individual decision.

No my boat isn't ferro, yes I do have a SS box that was made by a friend that is a fabricator for a very reasonable cost and my drinking water tank is made of Nalgene to limit the amount of plasticizers.

You only live once, you might as well live well.

[Typhoon]

Originally Posted by john61ct

For cheap and "good enough", where the boat costs less than some of these high end refrigeration systems,

assume a strong outer shell, then layers of rigid foam securely glued, so no flex or movement.

What would you think of this stuff just painted on, thickly and/or several coats, and call it done?

If not, what additional layer would be needed in between?

Never done this , but I suppose it would work as long as it does not eat the foam board. You could add some thickeners to it to get some build. The paint itself is very slow drying and will take many coats before you would get enough build to make it rigid.

Regards John

[exMaggieDrum]

I'm attaching the full specification sheet from the manufacturer of the FRP panels I am using. As I noted earlier I used these panels for a previous boat and they were odor free, durable, and easy to clean. They will crack and break if you cut off small strips of them but if backed up suitably they seem to really hold up. I am gluing them with epoxy to 1/4" glass reinforced panels and they are super strong.

They are spec'd as fiber-reinforced which are bonded with polyester resin. I have not seen anything indicating they contain styrene. They also seem pretty water resistant - 0.17% over 72 hrs per some standard test. I really don't have any concern about food contamination. It is a possibility I guess but I don't think it will be a problem.

The new panels I bought at Home Depot have no odor, or very little odor.

This may engender some discussion and I take full responsibility for being an idiot early adopter. I am going to use Loctite PL Marine adhesive to the upper transition to the rPart's vacuum hatches. It was rated a BestChoice by Practical Sailor Vol 44 No. 1 - Jan 2018. It rated higher than all the 3M products. It is a polyether and bonds well to FRP. The PS tests were done over a year on a roof top. I am not recommending it to anyone per se, it's just what I am going to try out. I really think it will work for this very well. Time will tell. I really don't want to try and do fillets at the transition. I would have to do them upside down from inside the box and the adhesive will be easier to do and work very well for this.

I haven't made a final decision on whether to use epoxy fillets on the interior box corners. The contributions above (thanks Delancey) are helpful to my thinking. IMO I think either well made fillets or the adhesive caulk sealant would work but the fillets will stay cleaner over time. I would also tape before doing the fillets for a clean look and use a structural filler with my West System epoxy. I love the pumps you can use to measure the great epoxy they make.

I am using Loctite expanding foam to fill voids behind my glass panels and around the Cryogel Z. One of my disappointments with the Cryo Z is that I could not get aluminum tape (three different brands including 3M's commercial grade best) to stick to the plastic liner. The dust from the mat prevented it from sticking. For the life of me I don't know how the manufacturer videos showed the workmen taping the stuff up easily. I tried cleaning the stuff with alcohol, and acetone, and water - no joy. So I am going to great lengths to seal all access to the insulation.

I coated all exterior surfaces inside I could get to with epoxy before I layered in the insulation to keep moisture from the exterior getting in. There were voids in some places around the insulation edges so I foamed them completely. The foam is very sticky and durable and 100% waterproof, closed, fine cell. I used a little of the large void foam that can only be used where the pressure it creates cannot break things. I used the lower expansion foam for most of it as I had mostly small voids. Both of them expand to fill all voids and cure with water vapor. Clean up before cure is with acetone. After cure it can only be removed by cutting and then sanding.

I am backing the FRP panels with rigid EPS pink foam board which will not absorb water (and doesn't really smell either). This will prevent water intrusion if screws are driven through the panels. I intend to have only 9 screw holes to mount the cold plate and I will seal those with the Loctite PL, both inside the holes and then under fender washers under my cold plate blocks.

I have put in two panels - the bottom and the hull side. The hull side was the hardest as it was curved and then pinched down at the transition to the bottom panel. So I layered the Cryo in like you would a fiberglass repair to build up the middle. There were 10mm transitions from the overlaps and I foamed those through holes I drilled in the structural FRP panel and the backing foamboard. These were spaced every two inches so it was a lot of holes. I am cleaning those up now as the foam extruded out the holes. I cut the excess foam off with my vibrating Bosch cutter (my favorite power tool next to my drill/drivers). Then I scraped the remainder and am sanding with 80 grit down to bare glass, cleaning with acetone and then covering all with the white FRP panels. I am very confident that I will keep ice cream and steaks well frozen.

I also have full confidence in my decision to go with the Cool Blue system. It is not cheap but it just plan works and has the best efficiency I have found. As I noted previously I had one before and it is still working on the boat after 15 years without any problems or downtime. (I have kept in touch with the new owners who sailed her from Australia to the Caribbean and now have her for sale. We used the system for 4 years full time liveaboard, half of that in the tropics, before we sold the boat.)

This is just a recap of what I am doing and much of it is based on contributions by all of you and other threads on CF. I appreciate even Bill O's comments about the FRP white panels. It has given me more to consider and research. I may be overthinking some of this but I want it to work for the next 15 years without a problem, which is longer than I will have the boat.

[exMaggieDrum]

Bill O sent me a PM as he thought you all might not care about but he is being modest and he gave me some info I found very useful about FRP, resins, materials, etc. that are commonly used on boats. I bookmarked it for future reference and some of you might like it too. It is heavy on the technical side but pretty easy to read anyway.

http://www.corrosionresistant.org/co...ke-composites/

Styrene seems to be a common, and most widely used, monomer used for resin manufacturing. I'm going to use the HD panels anyway and hope for the best.

Thanks Bill.