I mixed some up today for the first time… awesome stuff:cool:
No stink, even with the dye added. I use yellow dye, 3% of it. And you may think ’ awe 3% won’t tint all that epoxy.’ Nope it’s super concentrated liquid dye.
My question is how long should i let my first coat of 5 to 25 mils cure before adding the second tooling gel coat? 2 hours?
The resin I am using is a 1 hr pot life at 70F degrees. The temperature outdoors is 90F where i am working.
so this stuff you are using is epoxy based? What is it called? Are you brushing it on?
with epoxy gelcoat you would want to put the first layer down about 10-15 mils thick. let it tack up enough to leave a fingerprint but so nothing is left on your finger. the second should be applied thin just as a couplier coat and you should begin lamination immediately after apply(do not wait to tack). you should only do a few layers before bagging. do not attempt to do all your layers in one day unless it is a very simple shape and you can build it fast. typically a epoxy mold should be made over 3 days and a 4th day for attaching your back-up structure. a plastic squeegie applies the gelcoat the best in my opinion, be careful that corners do not have a build up of gelcoat, and you make sure during lamination that the corners get the butt of your material in the corners for the first couple layers
Thanks Hojo,
yeah i found with this epoxy 30 to 45 minutes works well between epoxy tooling gel coats. I did 3 layers of tooling gel coat, i wanted it thick enough for repairs and sanding if needed later on. This yellow is kick a**. Very bright, i love it.
I’ll start laminating in about 10 minutes or less, since i just applied the final tooling gel coat. I’ll do three layers of glass cloth 0,45,90 degrees lay up. I’ll bag it too for a few hours since this resin sets up kinda fast. This is fun:D
20_RC51… i made my own epoxy tooling gel coat. 4ounces of epoxy, heeping tablespoons of calcium carbonate dust, and 3% yellow epoxy dye. That did a seat cowl size mold with a 3" flange all around it. Mix the calcium carbonate to get a really thick pudding viscocity, after the epoxy part A and B are mixed for two minutes add the c/c. Then add the dye and stir it in real good. Should be rock hard when fully cured.
I highly suggest that you dont do 3 layers of gel, it is going to be too think, you will end up with chips and fractures in the gel long term. you really want total to be 15-20 max, no more. this will still be plenty to sand repair(if needed). if possible it would be best to have 10 mils. actually there are prepreg tooling cloths that use no gelcoat, which make them much more durable and last so much longer
since i have to roll and brush the epoxy gel coat on, it ranges from 15 to 40 mils thick, not even throughout. That is the total thickness of the gel coat.
I just did 3 layers of 3oz fiberglass cloth over that, then one layer of 10oz cloth. I bagged it and it’s under vacuum now. I’ll pull it out in a couple hours. It’ll have 3.5 hrs total in the bag. more than enough time.
Ah #@$% i just fixed the vacuum leak on my bag, then pulled a true 15hg… it bent the mold and cracked the gel coat i think. it’s still in the bag though, now under 5hg. My flange was too weak ( poster foam board, tapped with foil tape). Ah poop, next mold/flange will be mdf. what happened is there is an air space between the bottom of the plug part and the foam board base/flange, vacuum sucked all the air out of that space and buckled the foam board along with the lay up.
40 mils is too thick, next time use a plastic squeegie. as for the flange, you really need a hard flange to bag to, this is why I always suggest MDF. and always before making a mold you should do a vacuum test, bring it up to full bag pressure and unhook the vacuum and see how long it takes to leak, and plug that is well built and sealed should be ably to hold vacuum for 15 minutes before losing a HG assuming you also have no holes in your bag. having leaks in your plug can cause serious problems in the mold,so always take the time and do the test
fastrr can you post some pics of the thing in the bag?
yeah. no vacuum on it though, my stupid vac pump just died. Brand new too.
The brown color you see thru the bag is just my coffee table.
just my .2$s. gel coat is 1 product… tooling is a diff term. and epoxy surface coat is what your talking about. gel coat is ester based… so when saying, epoxy gel coat… thats a no no…
glad its working for u. i worked with this stuff on all my molds, i moved away from it and moved to gel coat. works easier.
Thanks Luisn. Yeah i just say gel coat so people understand better. You are correct the right name for it is epoxy surface coat.
RC51, the green stuff is the peel ply i used for this mold. It works good to create a secondary bonding surface, once peeled off. Kind of a rough texture it leaves behind. If the mold is ok, I will add 4 more layers of cloth and resin, bag it again.
ideally it is a better idea to use the natural peel ply when making epoxy molds, green release peelplys can leave the release behind, make sure you sand your mold real well and clean it before continuing with lamination
THnaks fastrr, I think I will give this stuff a try.
So you are just bagging it to get a nice and even laminate right?
looks like a solo seat cover?
Seems very involved for home production of simple cosmetic bike parts! Taking into account the above, and the extra costs involved, I am not sure an odor suppressed poly gel-coat wouldnt be more suitable.
Classic has it on the dot, i always cared about the smell… but with costs, etc i had to go with gel coat. i have 2 small shops and still have to care about costs. epoxy will always run more expensive.
looks like a 01-02 gsxr cowl.
Cost is obviously a major factor, and if you are thinking about small scale production, perhaps the additional cure time of epoxy systems over poly is also worth close attention?
Fast; You have highlighed one major difference between PER tooling and epoxy. Classic is right; because epoxy generally requires vacuum to consolidate the laminate, PER generally doesn’t (it can be “contact” moulded). This applies especially to mould making where it is sometimes almost impossible to pull a vacuum on the pattern.
However, I am impressed that you have experimented with your own surface coat (I agree that you don’t want to make it too thick,though). On risk of sounding repetitive, you shoud experiment with epoxy tooling compounds. These have the advantages of PER without the smell. Also they can be completed in one session.Still probably not as cheap as PER,though.Try making your own.
Fast; Have you thought of using casting resins? For the part in the photo, all you would need to do is create a wall all the way round the pattern and pour the casting resin in. Not the cheapest, but by far the quickest. No surface coats, no vacuum, no laminating, no smell!
be careful, i had a test sample quart size from , damn i forgot… but it was tooling compound epoxy . and MAN it was STRONGER then per… STRONGERRRRRR i almost fainted. it has amoina… (sp?)
freeman! there u go. thats the name