bigmike253

I am replacing all of the stringer and bulkheads in my 1979 formula 233 one side at a time. I am curious what cloth or woven mat I should use to tab and attach stringer with. Also how many layers and of what type of cloth I should use. I will be using west systems 105 resin epoxy. I looks like the original was one layer of woven roving over the wood. This boat will be running about 75-80mph top speed, so I'm looking for a solid feel and plenty of strength. Thanks in advance for any help.

glassdave

iTrader: (1)

when using epoxy you need a matless cloth this 1700 bi ax works well. You dont want to use any chop or continous strand mats in any epoxy systems, must be woven or linear fabrics. This 1700 will fill all the needs in any phase of your project. If you are doing the stringers and bulkheads in stages, epoxy must be ground down before subsequent laminations are applied (very important)

http://store.raka.com/biaxial1700-17...x-45x38in.aspx

Also while West System is a fantastic product it is very over priced. Look into uscomposites.com for their 635 thin resin with whatever hardener works for your situation.

bigmike253

Wow that cloth is pricey. I am able to get it for 4.04 around here. How. Many layers do I need? And by grinding between layer u mean with a 36 grit pad right?


Thanks for your help

glassdave

iTrader: (1)

Make sure the cloth you are pricing is 1700 and not 1708, very important that its not 08.

You don't need to grind between layers, only where you are applying wet on dry laminations or tabbing. 36 grit on a grinder offers the best mechalical bond. I usually do two layers over stringers and stagger in two layers of six or eight inch tabbing tape at the joint.

jackhammer

Why not 1708? It's been my favorite in some places. Sucks up the resin, but has good strength. I've put the mat side down and it's held for years in structural places (like connecting a bulkhead to the hull). What type of fail should i be looking for?

bigmike253

Hey Dave here is the stuff I was looking at purchasing:
http://www.fisheriessupply.com/produ...17OZ&cid=13712

Should I seal the stringers with a layer of resin before I put them in, then grind down and apply the cloth? Anyway do you think one layer would be sufficient or could I finish with a lighter cloth? Already the cloth alone will cost me around 400$.

glassdave

iTrader: (1)

if your going to run your 23 foot boat at 75-80 mph then no . . . . one layer is not enough

yes the stuff you posted will be the same. I prefer to do all laminates wet on wet, give the stringers a good coat before you lay on the glass.

glassdave

iTrader: (1)

you can use 1708 with epoxy but the mat ends up being a weak link in the laminate and it also is much harder to drive epoxy into. Try 1700 once and you'll be sold. Mat really has no place in any epoxy system, the random nature of the fibers offer no strength and in everything i have tested so far weakens it. If you do use it with epoxy it is better to put the cloth side down especially on those bulkhead to hull joints, you should also be able to balance a laminate with controlling resin wet out rather then sucking up excess (matless 1700 allows you to do this very easily). Excess resin drastically weakens a laminate as well as adding unnecessary weight. Sorry man i have been shoot'in down just about everything you've done lol. Generally it should work fine even with the mat side down but if your gonna use epoxy might as well capitalize on any properties ya can with modifying techniques. 1708 is ok but give 1700 a try and you'll be sold. Bout the only difficulty with a matless bi ax is when working with smaller patterns, they tend to be tougher to handle and want to distort or elongate while your trying to get them layed down. Handle with care


1700 for epoxy systems
1708 for poly or vinylester systems

timmoore

Hey BigMike... I was looking at Fisheries Supply and it looks like they are pricing cloth by the foot, not by the yard like most places do... just trying to help save you a few bucks. Mertons.com has it for $8.50 per running yard.

bigmike253

thanks, I was just there and picked up 55 feet of it. They charged me 96 cents a foot. Looks like they rang me up wrong....ooops...