Two new obsessions

[delmarrey]

Here's one of my toys. 5 Hp of metal munching machinery. It's not a CNC but for 1-ese & 2-ese a CNC is not practial. The time to set up and correct would take more time and material for just 1 or 2 parts.

CNC's are great for profiling, something a human can not do with just two hands (X & Y) and then try to keep them in sync. The 5 axis machines (X, Y, Z, xx, yy and/or zz) can perform miracles, it seems. They can carve out a human face in plastic in just minutes. But lots of $$$$$$

[knottybuoyz]

Originally Posted by delmarrey

Here's one of my toys. 5 Hp of metal munching machinery. It's not a CNC but for 1-ese & 2-ese a CNC is not practial. The time to set up and correct would take more time and material for just 1 or 2 parts.

CNC's are great for profiling, something a human can not do with just two hands (X & Y) and then try to keep them in sync. The 5 axis machines (X, Y, Z, xx, yy and/or zz) can perform miracles, it seems. They can carve out a human face in plastic in just minutes. But lots of $$$$$$

We've seen some of your work in the galleries Del! Amazing just the same. Since I was a kid I always watched my Grandfather, who was a tool & die maker, tinker away in his workshop. The mill and lathe just amazed me to no end. My uncle and cousin followed in his footsteps though. I have some mechanical apptitude but certainly nothing near that of a craftsman like you. I need more "near instant" satisfaction hence the CnC. Well hopefully.

[DeepFrz]

Rick, check out this link for some ideas of what you can do for your boat project.

Floats

[knottybuoyz]

Originally Posted by DeepFrz

Floats

Seen that Frz. One of the sites that got me really interested in resin infusion! There's plenty more and a few video's on youtube. HOpefully will have first project on the go soon!

[knottybuoyz]

to pull down a deep vacuum on a test piece. Results: "Failure"

Wrong materials (I got cheap stuff just to try this out)
Not enough pleats in the film (from what I've read this is the hardest aspect of getting a good seal)
Only leak I could find was around the vacuum inlet. I used cheap double sided tape instead of mastic.

Next attempt will use proper materials including the proper bagging film, mastic tape, foam core, flow media and fiberglass. You never know I might even plumb in some epoxy just for good measure.

[knottybuoyz]

why they don't use black acoustical sealant. What a mess! But I did get the bag down to 27In hg! Ok 'nuff playing around. Time to get the real stuff and do it right.

There's a good article in the latest Proboat magazine on repairing infused hulls. Professional BoatBuilder - August/September 2007

[knottybuoyz]

closer to actually spending (risking/wasting) some epoxy, foam & fiberglass!

I have the technique down to achieving a near perfect vacuum seal on the bag. Tomorrow we'll actually lay up a piece and mix up some epoxy. *keeping fingers crossed*. It ain't buildin' a boat but it is fun!

[knottybuoyz]

It's an odd shaped panel. Anyhow, have a look you experts. Any suggestions are greatfully appreciated. I'll have a crack at the other side after I get some feedback. It'll be another 20 hrs or so before I unmold this one.

It looks so much easier when the pro's on the Internet do it! I got a lot to learn before I ever dream of infusing the whole hull of our boat!

firstinfusion001.jpg is the stack layed up ready to pull the vacuum.

firstinfusion002.jpg is the stack with vacuum pulled.

firstinfusion003.jpg is after about 11 mins of infusion and the resin has already reached the vacuum outlet by running up the sides. I should have stopped the flow media and not allowed it to drape over the edge.

firstinfusion004.jpg is after the part fully infused at about 32 minutes.

[knottybuoyz]

First of all this process is a little labor intensive and probably not much economical benefit for one-off parts production. The benefit is your hands never touch the epoxy! The process is also wasteful. There are a lot of consumables involved, the resin flow media, peel ply, bag, spiral wrap, t-fittings, the butyl tape and the bag. I also wasted 25' of plastic line (forgot to cut it shorter) and a small resin trap I tried (too small).

The tooling surface is a 2x4' piece of malamine. 10 coats of release wax later you test it for adhesion with a piece of masking tape. If it sticks at all, more wax. This was the first time for this piece so I gave it a couple extra coats. There are other mold release agents available but I didn't try them.

It is vital to ensure that your layup will maintain a perfect vacuum after you shut off the pump. The clamping pressure is what maintains the ultimate shape of the part you're trying to produce. I'll explain later on what happens when you don't.

The location of your resin inlets and vacuum outlets are also critical to the success of the part. Seen here the panel is not infusing well. The resin was able to circumnavigate the part and reach the vacuum outlet too soon. This meant either pumping a lot more resin in (as I now know is wrong) or stopping the process and adjusting the flow media etc. (which is an extremely messy proposition.



I eventually got the entire part infused after about 32 minutes. About twice as long as it should have taken and using twice as much epoxy as required.

The epoxy I used is specially formulated for resin infusion. It has an ultra low viscosity and a very long working time (+5 hrs). For small parts like this the longer working time is more of a PITA than a benefit.

The completed part came out of the stack fairly easily. The peel ply did it's job perfectly. The resin flow media (nylon screen mesh) did stick to the tooling surface. There are some areas along the edges of the part that didn't stick due to loosing vacuum on the stack. What happened is the excess resin that was being pulled off the part kicked off in the vacuum line just ahead of the resin trap. This in essence shut off the vacuum to the stack. After that there was no way to get the whole layup back under vacuum. I had planned to trim the edges anyways.

Frontside

Backside


The larger flat surfaces of the part are perfectly infused. There are absolutely no bubbles or areas where there shows any resin starvation or delamination. Both sides of the part were infused at the same time and I was a little worried about the backside (laying on the tooling surface) not getting resin. No worries there. The flow media looks after that.



The biaxial fabric is 1708. Amazing product! A little awkward to handle such heavy fabrics and it takes some getting used to. A little 3M Super77 adhesive was req'd to keep things from moving around too much when setting up the stack. The peel ply a fine weave nylon fabric left a very smooth surface. It would probably need some light sanding for a secondary bond. I'm just guessing until I cut into the part but I figure there's 40% resin and 60% fabric. Maybe a little less resin but not much.

So the things I learned are:

Proper location of the resin inlet and vacuum outlets are critical. Experience necessary I think so that you can judge when/how the resin will reach the outlet AFTER the part is fully infused (Ideally).

Having a perfect vacuum seal on the layup is also critical to the complete success of the final part. Any leak, no matter how small is unacceptible. An ultrasonic leak detector, such as those used in the refrigeration repair industry would be a big benefit.

A bigger resin trap is required. Mine was only about 5 oz, sort of an inline filter thingy. I have my eye on an old paint pot at the local flea market that'll work. Shorten your vacuum lines so you don't waste them if you suck in some resin.

Heat lamps and hair dryers are good to help control the flow of resin. As soon as the part is fully infused we lit the exit area with lamps to help the resin kick off quicker. This helped a little bit in restricting the flow of resin, as it will with a sustained vacuum applied. Downside is it prevented us from reapplying vacuum when we needed it. Two vacuum outlets, a primary and a backup is maybe a good idea.

I'll probably do the other half next week. Need to acquire a few more materials. Hopefully it'll go better. Will post the results as well.

I'm thinking all this tinkering with this process might lead to being able to produce some smaller parts for our project, hatch covers, etc. We'll see. I don't think I have the stones to try this on the whole hull of a TW28!!! That's risky beyond belief (for me anyways). I've seen it done on the Internet but without professional guidance I don't think I'd even attempt it (feel free to remind me of that)!

[DeepFrz]

Rick, I think what you need to do after you have complete infusion is to cut the flow of resin in and leave the outlet free so you keep the vacuum untill the whole thing kicks. I have seen some large projects (hulls) where there were extra ports installed but left sealed until needed. Also I have seen references to installing extra vacuum ports in areas that were not getting any flow. This was done as the part was being infused in order to save the part. I'm not sure how this was done.

I have never done this, it's just stuff I picked up in reading, so take it for what its worth.

Perhaps a kit from Henny would be a worthwhile expenditure?

[DeepFrz]

A comment on your thoughts about infusing your hull. I would recommend if you were going to do this you should pay for a flow analysis. You are right that doing it wrong would be a huge mistake. However, I think that there are enough resources out there that could help you make sure that it is done right. I'm not sure of the costs though and that might make the difference.

After infusing some smaller parts and gaining experience you may well change your mind and go for it.

[Boracay]

Sounds like a really tough way to build a one off.

How do you think it would compare to using a really heavy unidirectional lay up and doing one layer at a time?

When discussing older fibreglass layups the main concerns are thickness and no voids.

If I was ever to build another boat I would plan on doing it inside out. That is, build the interior upside down on the completed deck, then do the stringers, with the hull last.

Could be very fast.

[knottybuoyz]

Originally Posted by DeepFrz

A comment on your thoughts about infusing your hull. I would recommend if you were going to do this you should pay for a flow analysis. You are right that doing it wrong would be a huge mistake. However, I think that there are enough resources out there that could help you make sure that it is done right. I'm not sure of the costs though and that might make the difference.

After infusing some smaller parts and gaining experience you may well change your mind and go for it.

You're right on all accounts Frz! I have the software (Polyworx). What I have to do, with the designers help, is digitize the hull. It's the same software used on that Dutch site you mentioned before. After digitizing the hull it looks pretty straight forward from there.

There actually isn't too much risk involved in doing a hull even with an incomplete infusion. You can, after the hull cures, is re-infuse the sections that were starved of resin. I saw a demo of that somewhere and it wasn't a real big deal. The biggest risk is in mixing errors with the epoxy. Not getting the ratio's right and not mixing thorougly enough can lead to big problems. Just imagine a 30' hull soaked with uncured epoxy and glass. Having to strip that off and start again would be a heartbreaker.

Originally Posted by DeepFrz

Rick, I think what you need to do after you have complete infusion is to cut the flow of resin in and leave the outlet free so you keep the vacuum untill the whole thing kicks. I have seen some large projects (hulls) where there were extra ports installed but left sealed until needed. Also I have seen references to installing extra vacuum ports in areas that were not getting any flow. This was done as the part was being infused in order to save the part. I'm not sure how this was done.

I have never done this, it's just stuff I picked up in reading, so take it for what its worth.

Perhaps a kit from Henny would be a worthwhile expenditure?

The fella's on the infusion bbs have been telling me to cut the resin whent he piece is about 80% infused. The leading edge will be resin rich and over time, keeping the vacuum up it'll bleed out filling the piece. If you watch any of the video's on youtube you'll see them do this. The resin flow slows but does not stop. It'll eventually level itself out. It takes some practice.

I think I'll have a backup vacuum line ready next time. Might also double bag. One to infuse the part and the other to clamp it after infusion. Just another method to test out. Watched a guy repair a hole in a boat and that's what he did. After the infusion was complete he clamped off the inlet and outlets then pulled the vacuum on the second bag to clamp it. What that did was prevent the vacuum from pulling more resin out of the repair. He was working on a vertical surface, which doesn't really matter I guess, but only let the clamping HG get to about 20. Once the resin kicked he let the vacuum off and inflated the bag. He then set up a heat lamp to expedite the process or post cure I think.

I'll keep a pair of Tyvek coveralls with your name on them ready when we start the hull Frz!

The kits are expensive. I've got pretty much everything except the paint pot (vacuum reservoir/resin trap) but that'll be corrected tomorrow!

Oh, did I mention it was FUN?

[DeepFrz]

Rick, I didn't realize that you had polyworx. Great.

Have fun and I wish I could give you a hand. But the way things are I will have to enjoy it from here.

[knottybuoyz]

Originally Posted by Boracay

Sounds like a really tough way to build a one off.

For one-off small parts you're probably right, at least that was the conslusion I came to fairly early on. Other than the whole process is fun (I know I'm a sick person) it was interesting to watch (if not a lot like watching paint dry). I think the process is better suited to creating superior parts which are lighter and stronger than can be achieved by cold molded lay ups. IMHO

Originally Posted by Boracay

How do you think it would compare to using a really heavy unidirectional lay up and doing one layer at a time?

I have no doubt, based on what I've seen (been studying this for months and seen a few jobs done) and learned just from this one small test that this is a far superior process that would result in a much stronger & lighter hull. The ability to control the resin flow and vacuum pressure would allow you to reach the absolute ideal resin to glass ratio. The biaxial fabrics with mat backing are just like 3 layers of glass in one.

The cost of the consumables is offset against the crew you'd have to cajole into helping (and feeding and watering etc.) plus the mess. When doing a multiple layer hand layup you'd ideally want to work wet on wet (for a good chemical bond) which means you'd have to have a good system going and depending on how big the project some slow epoxies.

The ability to lay out the fabrics dry, trim to fit, correct overlaps etc. gives you plenty of time to get it right. Take as much time as you like. Only when you're completely satisfied it's right do you bag it and infuse it. Once the process starts all you have to do is stand back and watch (consume favorate beverages).

Originally Posted by Boracay

When discussing older fibreglass layups the main concerns are thickness and no voids.

I think one of the reasons this process is so much the norm now is the lower liklihood of voids appearing in the layup. If you're careful with your fillets (adequate radii (sp plural of radius)) etc. to prevent bridging you can almost totally eliminate any voids. The small test I did had no voids and the fabric was completely saturated and compressed. I'll cut into it tomorrow and try to get a pic of the cross section. The thickness required to give a panel strength comes from the core material. In the case of our boat it'll be marine ply. In this test I did it with plain styrofoam insulation board and it is incredibly STRONG!

Originally Posted by Boracay

If I was ever to build another boat I would plan on doing it inside out. That is, build the interior upside down on the completed deck, then do the stringers, with the hull last.

The hull we'll build is stitch & glue ply built over a strongback frame. It doesn't get much simpler than that. Consider the panels will be CnC cut it should (and has for others) gone together very quickly and easily. (fingers crossed).