How much resin?

[SgtMaj]

How much resin would be needed for 25 yards (55" wide) of 6oz fiberglass cloth?

 

[BillP]

Re: How much resin?

229.14 oz.

 

[SgtMaj]

Re: How much resin?

Really? That's less than 2 gallons. Well that won't break the bank. Cool. Thanks.

 

[Robj]

Re: How much resin?

If that is less than 2 gallons, I think your calculations are way off for 25 yards at 55 inches wide. My guess would have been more like 20 gallons, but this is only a guess. No offence BillP, but you may want to recheck your calculations, you maybe out by a factor of 10.

Have a great day,

Rob.

 

[BillP]

Re: How much resin?

No offense taken and corrections are always welcome. Math is way better than guessing...but for estimating (in a 50/50 saturation world without waste) it's 1 oz of resin for every 1 oz of cloth (per sq yd for cloth and per sq ft for mat). Calculate it at whatever saturation you think (40-70?) it will be and add waste.

Area is 38.19 sq yds.

bp

 

[rockyrude]

Re: How much resin?

I'm in a similar spot, getting materials for a rebuilt. If I understand your calculations I should be able to use 6 oz of resin to glass one square yard of 6 oz cloth, correct? What do you mean by 50/50 saturation? I thought the glass needed to be completely saturated.

 

[SFT2]

Re: How much resin?

50/50 meaning half of the resulting composite is glass and half is resin.

 

[Robj]

Re: How much resin?

Sorry BillP but my comment was based on experience. I still do not think it is possible to saturate that much mat with less than 2 gallons of resin. I used more resin than that when I glassed the top of my deck, and nowhere near that amount of matt. Just sounds unrealistic to me.

Have a great day,

Rob.

 

[rjezuit]

Re: How much resin?

It is 6 oz cloth, not mat. An amateur may not be able to get to 50% glass/resin. But either way it's less than 2 gallons at 128 oz per gallon. I agree with the math. 38.19 yards X 6 oz per yard = 229.16 oz.

 

[BillP]

Re: How much resin?

Sorry BillP but my comment was based on experience. I still do not think it is possible to saturate that much mat with less than 2 gallons of resin. I used more resin than that when I glassed the top of my deck, and nowhere near that amount of matt. Just sounds unrealistic to me.

Have a great day,

Rob.

Yep, I can relate but the numbers say what is the highest strength with resin. 6 oz cloth is WAY lighter than the commonly used 1.5oz mat...I didn't mention earlier that mat (measured by sq ft) takes 2 oz of resin per 1 oz of cloth for estimating...1.5 oz mat would take 27oz of resin per sq yd or 8.05 gals plus xx% waste for the same 38.19 sq yds. If you don't do the math for resin content it just leaves more room for error.

I was trying to avoid going into a long explanation but because of variables it's hard to give one general answer for how much resin it takes. Anyone can do the math for perfect saturation but the rest is up to the user. It's just not an exact science except where ratios are calculated. Variables...When priming wood or foam first add 10-20%. If using a brush or roller to apply and work the resin add more. (lots more)...a squeegee does way better for controling resin thickness, ESPECIALLY on light cloth. If needing fill coats for sanding add another 30-50%. How much runs off? How much is left in the mixing bucket, etc, etc? As mentioned already, skill level pretty much dictates how much is used over and above the "ideal" 50 glass/50 resin ratio (1 oz to 1oz for cloth - considered by most mfgs as a standard benchmark for getting the best results).

Anyway, that's my story and my wife and her dog says I'm sticking to it.

bp

 

[boatguy19]

Re: How much resin?

around 3 to 4 gallons for 25 yards

 

[SgtMaj]

Re: How much resin?

Ok, well I will probably go with 4 gallons of Hexion Epon 863 epoxy then, and I plan to use a bakers spatula to apply it. Knowing myself, I think I will have a much easier time with that.

 

[ondarvr]

Re: How much resin?

I think BillP covered it pretty well, the waste is the main variable.

 

[SgtMaj]

Re: How much resin?

Yeah, and there are some areas where I plan to build up more resin, possibly up to 1/4 inch thick, but if I have to buy more later I will. From the sounds of it though, those 4 gallons should at least do the bow (I'm estimating the bow will use about 4-5 yards and there won't be any build up areas in the bow. Depending upon how much I have left, I may work one or both of the gunwales, and/or the upper deck also.

 

[ondarvr]

Re: How much resin?

What do you mean by build up with resin to 1/4"?
What type of repair are you doing and what type of resin are you using? It can make a difference in how you do the job.

 

[SgtMaj]

Re: How much resin?

Not really doing so much of a repair as just adding a slight reinforcement to the general hull. Those buildup areas are just where it's currently uneven (one top of one of the gunwales is slanted slightly outward, just enough to bother me. It's nothing that would ever be under any stress though). I'm planning on using epoxy resin (due to epoxy having a greater molecular bond than polyester resin). Specifically Hexion Epon 863 epoxy.

 

[ondarvr]

Re: How much resin?

I forgot you mentioned the epoxy earlier.

One 6 oz cloth won't add much strength and is almost a waste of time and money if you're just laying it down on the inside of the hull.

With no stress, 1/4" of epoxy may hold up, but any flexing and it will crack, so use glass to build it up.

 

[Robj]

Re: How much resin?

Thanx BillP for the reply and for the clarification. I must admit that I am not an expert at fibreglassing which is why I used more than was probably required. Also I did use matt not cloth. Your explanation makes sense.

Have a great day,

Rob.

 

[SgtMaj]

Re: How much resin?

I know it won't add much strength to it, but that's ok. It will make me feel better about it. Right now it crackles when I'm walking on it while repairing the deck, etc... and I just don't like that sound, so I just want to add a little something to it. But I don't want to add much weight to it at all, so that's why the 6 oz. instead of something like 18-24 oz. (I will use that heavy stuff for the transom repair).