Re: Some specific fiberglassing questions for you fine folks
Ok, so as a few of you may know, I'm in the process of restoring a 19' sea ray (year unknown). I've determined that I'm going to have to replace all 4 stringers, the deck, and build up the transom to convert from i/o to out board. I believe I understand the concept of what has to be done, just not what is required to do it.
Obviously no one is going to be able to say 'you need x amount of hardener, y resin, etc." So I'm hoping someone is able to tell me the aproximate amount of hardener, resin, and glass mat I should get.
Also, what brand/type should I be looking for?
And to apply the resin, should I just use regular paint brushes and rollers, or are there specific resin rollers? Aaaand lastly (for now, heh) what kind of place should I go to get these types of things, I'm guessing the Home Depot is probably not the best place to go?
Thanks for your consideration,
-sam
Rollers (for saturating the chopped strand mat with resin) should be the cheapest you can find (but not foam ones as these fall apart easily). Consider them disposable after each session as the effort of cleaning them is not worth the cost.
Rollers (for rolling air pockets and driving the resin through the CSM) should be an aluminium paddle type - best to get a small one for small areas like your stringers, and a large one for the deck.
Brushes (for pushing the resin and CSM into corners etc should be available from the resin/csm supplier in bulk packs of a dozen (again, not worth the effort to clean if they are cheap enough.
Type / Brand - Well Epoxy resins cost a lot, and if you are doing a transom, stringers, deck and other bits and pieces - you will need a lot. Polyester resins are much cheaper, and here in the UK we get what is called General Purpose polyester resin approved for marine use.
I have used 50 litres of the stuff so far, but then I have glassed the entire internal hull, new transom, new stringers, new keel (also used polyester resin for this with a filler powder) new bulkhead and still haven't done my deck yet.
Polyester resin with a filler powder is great for fixing the stringers and transom into place prior to glassing with CSM.
Resin to catalyst mix can depend on what you want to do. Note, below refers to polyester resins only). If at 20 degrees Centigrade, a 2% catalyst to resin mix will give 20 mins working time - this is not long if you are starting out and practicing. Mix your very first batch as small as possible, and use 1% catalyst - just so you get the hang of things. So make up 250 ml of resin with 2.5 ml of catalyst for the 1% mix and go and play with something easy to get used to it. (I use a syringe for the catalyst)
As you get more confident with it, make bigger batches, and maybe go for 2% catalyst to resin mix to speed up the reaction.
Some things work strangely - laminating onto wood takes longer to cure than laminating onto other fibreglass, painting your resin onto bare wood takes forever to harden, even though you maybe mixed it correctly (not a problem, just don't worry if it is still damp after several hours it will eventually set. If you need a quick mix go for 3% catalyst.
If you keep using the same pot for several mixes in a row - be aware that the residue from the last batch is still in the pot (unless wiped out thouroughly) and will affect the working time, so you will notice shorter gelling times.
The same roller and brush can be used for multiple mixes - but only if you keep at it - stop for an hour lunch break and they will be hard when you get back, so plan to do your glassing for a few hours at a time to keep the brush and roller active to prevent them being wasted too quickly.
Only mix what you can work with within the time period of the mixed batch.
Two people can make a huge difference, as one is rolling out the resin, the other can be paddle rolling the saturated mat, and then the other can mix more etc - probably 4 times faster progress than one person on they're own.
Don't ever scrimp on the resin quantity - cover the area to be glassed with resin, lay the CSM and then fully saturate the CSM so that it turns totally translucent after being rolled. If after this the appearance of the CSM is still milky white - then you haven't used enough resin to disolve the mat bonding agent properly (the stuff that give it its white colour. Rule of thumb is for every 100 grams of CSM you need 250 grams of resin. Too much is better than too little - but please play about in the early stages on something not too important to get used to it.
Good news - if you make a right mess of something and don't like what you did - just grind off the bad bits and redo. This stuff is very forgiving.
Sorry for repeating some of the info already given, but I got into a bit of a flow there
