gelcoat/skin coat lamination issues

[goodwrch]

I am a amateur boat builder working at home, I have had a problem with my skin coat lamination on several layups so far, Im getting voids where the first layer of mat is not staying in contat with my gelcoat. the problem is occuring in the hatch areas of the deck and chine/strake areas of the hull, basically where there is a sharp bend or corner. I have started using a puddy to fill in the areas after my first couple layers are hand layed to ease further layups, my question is........does anyone know if you can use the puddy against the gelcoat, its a catalist hardened puddy, and would elimate the pain of hand laying strips around all the hatches...pics are attached of my delemas, thank you for any and all responses.

[Reese]

guess there is a time delay.

No matter...I'm also glassing my project boat and yes, the outside corners are always the most difficult to get the glass to adhere.

One technique you may want to try (only with Laminating Resin) is to coat whatever area you intend to glass over and let the resin sit untill it's very sticky.

Apply your cloth (this won't work with mat) over the area and press down with your hand, squeegy, or cardboard...it should stay put. Wait at least an hour after you've applied the cloth before resinning over.

It's always best not to have sharp corners when glassing but sometime it's unavoidable and this technique works pretty well. Good luck.

Yes, you can use a catalyzed putty like Kitty Hair over the gel coat.

[Jeff]

pics are attached

The picture(s) didn't make it to the server for some reason... maybe you could try posting them again? (You can only attach one picture per post in the forums and it works best to keep them fairly small, jpg format...)

[goodwrch]

here as pic with puddy....

[Reese]

or just the rectangular area with the putty...?

Any Bondo type of catalyzed body filler will work for fairing but I would suggest using Kitty Hair for anything below the water line. Another product that works well for fairing out sharp corners is cabasol...a thickening powder that is mixed with resin.

Try my suggestion of brushing on a coat of laminating resin and waiting for it to set up...the reason this technique does not work as well with mat is because it uses a binder to keep all those chopped stands in place. If you completely coat mat with resin and try to get it to stick around a sharp corner it will want to pull away and leave a void.

Cloth is much easier to work with, especially around sharp corners and difficult contours. You can also buy cloth in pretty heavy weight up to roving which is for heavy layups. For all those reasons I don't use mat any more...it's not that easy to work with, and the finish is pretty horrible.

[goodwrch]

After two layers of 3/4 oz mat i filled only the hatch lip/valley with the puddy, it certainly made the remaining laters easier to layup....Ive never heard of kitty hair.....anything like summer blend? When you say you arent laying up mat anymore, what is your skin coat and doesnt anything but mat show a print thru?
thans so far with your suggestions.

[Reese]

I may have not read your orginal post clearly. Are you trying to repair or patch a particular area of a boat, or are you having difficulty with the fiberglass sticking to the gel coat of a boat mold.

If it's a mold issue then yes, use mat veil for the first couple of layers, and then apply your cloth.

Kitty hair is reinforced glass bondo made by evercoat...they make two versions, short strand and long strand...use the short.

[Lew Morris]

Cab-o-Sil. It's fumed silica. You mix it with your laminating resin to make a putty the consistency of peanut butter (or thicker). You can get it at a well-stocked fiberglas materials distributor. I'll see if I can locate the cab-o-sil website.

Smear a generous fillet into sharp corners. It will bridge the gap that ( you now know) that mat can not form into.

Try a test layup over a couple of pieces of 3/4" plywood. Apply the putty directly to the gelcoated surface using your fingers (in a rubber glove of course). For a radius . After the putty is down IMMEDIATELY start your lamination. iF YOU ALLOW THE PUTTY TO KICK OFF BEFORE YO LAMINATE YOU WILL HAVE HELL TO PAY trying to smooth the spikes of hardened material off.

Use this material any time you are trying to laminate over, or into something. Don't use a huge amount, just enough to bridge the gap.

A little resin goes a long way when mixing. Start with a quarter-cup of resin. Catalyst it "hotter" than normal and then start adding the Cab-o-sil. The reason you catalyst hotter than normal is because the cab-o-sil displaces the catalyst/resin matrix and essentially makes the molecules farther apart... the additional catalyst helps over come this.

I hope this isn't too confusing. you're on the right path...yes you can apply putty to gelcoat...don't use bondo ... it goes off too fast... WAY too fast.


go to this website too:

www.fiberglast.com

[Lew Morris]

see: www.tapplastics.com

go to: Fiberglas Tools & Supplies

[Lew Morris]

then go to: Resins Fillers & Dyes

If you are mainly having problems in the small corners could it be you are putting on to many layers of glass at once and you are not able to remove the air,or having resin starved glass? I would suggest using just one layer of 1 oz csm first, then once this has hardened adding more layers of heavier csm at once.

[raceday]

I would suggest 3M's micro balloons over bondos, kitty hair and cabosil, cabosil is very brittle and and has a tendency to crack and shatter. 3M's Micro Balloons are very light and strong.