Wood That Won't Warp For Building Entire Kitchen Counter, and Advice On Building Hatc

[albergsailor]

Thats looks very well done. I was wondering what the reason was for glassing that piece of wood in the middle of the hatch. since it looks like the plywood does not rest on it

[salticrak]

Originally Posted by atoll

the finished article

Gordon Bennet! nice work with the itchy and scratchy stuff mate.

[Richard5]

Listen to Atoll. I used to use sheet vinyl for hand lay-ups of fiberglass panels in building canoes and small boats. To be a bit creative sometimes I used the sheet vinyl with a pattern face. And yes, the PVA release works great.

Gel coat has several purposes of which a mold release is the least. Gel coats are crosslinked which lends durability and fills any micro holes in the matte/cloth/roving thereby making a smooth surface. A significant purpose of gelcoats is UV resistance. "Bare" fiberglass (cloth and resin, as example) will degrade from UV and water. Gelcoats reduce the permeabilty of the fiberglass lay-up.

Even a cursory examination of a fiberglass hatch cover, such as on production boats, will reveal that the bottom edges of the lay-up which is not sealed by gelcoat will be less durable and are likely to splinter and, over time, will show water penetration. It is the absence of the durable gelcoat which is the culprit.

[Richard5]

Originally Posted by albergsailor

Thats looks very well done. I was wondering what the reason was for glassing that piece of wood in the middle of the hatch. since it looks like the plywood does not rest on it

I would say 1) fiberglass has little tensional strength and a structural member is required, 2) it's hard to tell from pictures.

Without structural support, the fiberglass lay-up is prone to flexion which leads to fatigue cracking and splintering.

[atoll]

Originally Posted by albergsailor

Thats looks very well done. I was wondering what the reason was for glassing that piece of wood in the middle of the hatch. since it looks like the plywood does not rest on it

you are quite correct the ply does not rest on the central batton,it is there to add stiffness should the hatch be walked on,probably overkill as the voids are also filled with expanding polyeurathane foam for insulation,and filling any gaps behind the plywood.

[atoll]

Originally Posted by Richard5

Listen to Atoll. I used to use sheet vinyl for hand lay-ups of fiberglass panels in building canoes and small boats. To be a bit creative sometimes I used the sheet vinyl with a pattern face. And yes, the PVA release works great.

Gel coat has several purposes of which a mold release is the least. Gel coats are crosslinked which lends durability and fills any micro holes in the matte/cloth/roving thereby making a smooth surface. A significant purpose of gelcoats is UV resistance. "Bare" fiberglass (cloth and resin, as example) will degrade from UV and water. Gelcoats reduce the permeabilty of the fiberglass lay-up.

Even a cursory examination of a fiberglass hatch cover, such as on production boats, will reveal that the bottom edges of the lay-up which is not sealed by gelcoat will be less durable and are likely to splinter and, over time, will show water penetration. It is the absence of the durable gelcoat which is the culprit.

+1 the gelcoat also allows for invisible repairs if there are any imperfections or later scratches on the surface,that can be filled with gelcoat,sanded and buffed out.

[atoll]

Originally Posted by salticrak

Gordon Bennet! nice work with the itchy and scratchy stuff mate.

more like heath robinson eat your heart out!,
i find if you lay out all your tools and pre cut/tear your cloth,keep acetone and rags handy it does not have to be a sticky mess!

when grinding glass if possible i will take the item outside,and with the wind at my back commence the work,with the wind carrying way the majority of dust, afterwards blowing off with compressed air any dust on hands and clothing helps as well,this way very rarely do i get itchy and scratchy!

[albergsailor]

well i grabbed a 1/2in and a 3/16 4x8 sheet of mdf. a miniscule bottle of pva from west marine for 16 dollars. I could not see myself paying 16 or 23 dollars for a resin roller at west marine. So im goin to try and get to a composite store tommorrow anything else i should grab while im there? Im getting fiberglass matt, a cuple resin rollers, part all #2. I guess i shud get more pva at a more resonable price as well

[Richard5]

albergsailor, how do you plan to measure resin and catalyst? You have to measure by volume not weight.

Be sure to pick up some foam pads for backing sand paper, in proper grits or course.

[atoll]

you will need acetone,for cleaning you hands and tools,brushes.
also a 5liter bucket with a lid,for cleaning brushes and rollers in if you want to use them more than once.

i normally buy a pack 12 of 3" rollers,works out at about 50c each

normal floor wax will work as well as a release agent,as will liquid soap on very shiny surfaces

if doing big jobs a cheap kitchen scale is useful for measuring the weight of resin so you can get an exact weight of resin,and add the correct dose of hardner.

hardner i buy in 200ml quantity which comes with a measuring reserviour in the top,with 5-10-15-20-25 ml marks on it.

resin i generally buy in 20 kg tins,as it works out a lot cheaper

gel coat i generally have a 5kg tin onthe go but they should supply in 1 kg tins

chopped strand matt i use 300 or-450 gsm depending on the job,300 is better for sharp corners.

1 1/2" disposable brushes you will need as well.

thin cutting disc's are usefull for trimming,and 40-60 grit sanding discs for your grinder.

for mdf predrill your screw holes and countersink,a selection of posi drive screws for building the mold,pine battoning to reinforce the mold.

if the mdf is not melamine faced you need multiple coats of release agent.

generally 1 kg of resin gives saturation for 2m/2 of 450g cloth,less if doing multiple layers

if you dont have a scale 1liter of resin you need 10-20 ml hardner,this will give a 1-2% mix,if it is hot use 1% or in coldder weather 2%(20ml)

pm me if you need advice urgently!

[minaret]

Originally Posted by albergsailor

well i grabbed a 1/2in and a 3/16 4x8 sheet of mdf. a miniscule bottle of pva from west marine for 16 dollars. I could not see myself paying 16 or 23 dollars for a resin roller at west marine. So im goin to try and get to a composite store tommorrow anything else i should grab while im there? Im getting fiberglass matt, a cuple resin rollers, part all #2. I guess i shud get more pva at a more resonable price as well

Don't try to use PartAll and PVA together, it won't work. Use one or the other. If you use PartAll first and then try to PVA it, it will just bead up on you and then run. PartAll is easier to work with than PVA and gives a nicer part IMHO. You just apply it with a rag, let it dry a little, and hand buff it. No spray like PVA. It never fails.

[Sand crab]

For your countertops try using oak or maple butcher block. You can order it in just about the size you need and it's bullet proof even if it gets wet. Use the cutout for the sink as your cutting board. Build the cabinet out of the matching ply if you want.

[albergsailor]

Originally Posted by Richard5

albergsailor, how do you plan to measure resin and catalyst? You have to measure by volume not weight.

Be sure to pick up some foam pads for backing sand paper, in proper grits or course.

I was just gonna drip sum hardener into the mix and hope its enough. Come on man im not that stupid, but thanks for bringing it to my attention . Ive always followed mixing directions when fiberglassing and off the top of my head i think its 12 drops of hardener to an ounce of resin. It always worked just fine for me. Of couse im using the bondo brand resin which im sure isnt the best or least expensive, but since i already have a bunch of it thats what im using.

Thanks so much everyone for all the support ive been extremly busy trying to make money so thats y this project hasnt started yet. This composite store is one of those" order by phone then pick it up we dont like to deal with the public kinda stores" and its a half hour away, so that sucks but watta ya gonna do.

[Richard5]

alberg, my apologies if I sounded condescending. I, like most folks, am willing to lend what I know and from your questions it seemed you were inexperienced. I'd say I have an extensive experience with fiberglass from shaping and glassing surfboards, to hand lay-ups of small boats, to marine repair, to being west coast chemist for Dynatron/Bondo...I have seen failures galore with poly- resins. I certainly don't think you stupid.

[atoll]

i use something like this for bigger jobs,and a small set of kitchen scales.
if you are doing a big lay up,and want to have enough time before the the lower layers kick off it makes life a lot easier!
i generally mix in batches of 1kg for straight forward small molds,or 500g for fiddly ones with lots of corners.

Catalyst Dispenser Squeeze Bottle Fiberglass Supply