Quantities of resin for area of coverage

[NatedoggAZ]

Hello everyone,

Is there a chart - or some sort of calculation available that can determine how much resin is needed to coat/cover a certain amount of surface area?

If I am going to brew up a batch of resin - I want to be sure it will be enough for the job I am doing. If I brew up a little more than I need - no big deal, but if I am only partially the way through a job and have to stop and brew more...that would be a pain.

So - for instance... If I want to coat one side of a 3x3 sheet of bare plywood with a layer resin, how much resin would I need to make?

Looking for an "x" amount of resin to cover "x" square feet of area.

Understanding also that depending on the hardwood you use and the different densities of the wood could be a determining factor in the absorption rate of the resin into the wood...

... I'm just looking for a baseline in where to start in the quantities...

----------------------------------------------------------------------------------------------------

Using actual fiberglass in coordination with the resin would be a different calculation due to the absorption rate of the resin into the glass - which would yield a totally different amount of resin needed... If someone has estimates for that as well - that would be great!


Thanks!

ND

 

[gm280]

Actually most boat supply places that sell both epoxies and polyester resins do tell you the amounts. However, when you are talking coating wood of any type, that is merely a suggestion because different woods soak resins at different rates. If you are covering previous cured resins, their suggestions are pretty right on. But if you are covering new woods/plywoods, then you will certainly need more then suggestions. Either way, if you are covering most anything and run out, it only takes a few minutes to mix more and you shouldn't have any issues either way. Check with US Composites for coverage suggestions. It also depends on the weight of the fiberglass material you are using. JMHO!

 

[NatedoggAZ]

OK cool - Looking for polyester resin coverage...

US Composites had a calculation for epoxy resin. "... a typical 4'x8' sheet of plywood would require about one quart (32oz) to seal both sides."

Not sure if that also applies to polyester though...?

ND

 

[NatedoggAZ]

Also found this from US Composites for Epoxy resin... looking for the Polyester equivalent:

[SIZE=-1]Chopped Strand Mat (CSM): Approx. 2 pounds of resin for 1 pound of mat
Biaxial (1708,1208,1808): Approx. 1-1/2 pounds of resin for 1 pound of biaxial

ND[/SIZE]

 

[Woodonglass]

Your request is almost impossible to answer. All woods absorb at different rates. Temps,Humidity etc all play a factor. In most cases 1 quart of Poly will adequately saturate 3 sq ft of 1.5 oz CSM or 1708. This DOES NOT account for the precoating of the plywood prior to the application of glass. It also does not account for the person doing the work. Less is more when fiberglassing sooo someone that's in the know will always use less resin than the beginner. With poly using to much resin is almost as bad as using to little but as in all things, it's always easier to add more than it is to take away to much. This is a good guide but still will Not account for the many variables.
Google How mush resin do I need and then look for the F i b e r G l a s s i t e link

THE GENERAL RULE FOR CHOPPED STRAND MAT IS YOU WILL NEED 1.5 TO 2 TIMES THE WEIGHT IN RESIN AS YOU HAVE IN CLOTH . SO 1 POUND OF CLOTH WILL NEED 1.5 TO 2 LBS OF RESIN. TO MAKE IT EVEN MORE SIMPLE, 1.5 OUNCE CHOPPED STRAND MAT WILL NEED 4 OUNCES PER SQUARE FOOT, AND TWO OUNCE CHOPPED STRAND MAT WILL NEED FIVE OUNCES PER SQUARE FOOT. BUT REMEMBER , THE SUBSTANCE YOU ARE FIBER GLASSING OVER WILL ALMOST ALWAYS SOAK UP RESIN ALSO, SO WE ADVISE OUR CLIENTS TO USE 4 OUNCES PER SQUARE FOOT FOR 1.5 OUNCE CHOPPED MAT, AND 5 TO 6 OUNCES PER SQUARE FOOT FOR 2 OUNCE CHOPPED STRAND MAT.

MATERIAL..........................................GALLONS

1.5 OZ MAT = 1 gallon covers 4.2 square yds

2.0 OZ MAT = 1 gallon covers 3.4 square yds

THESE FIGURES DO NOT ACCOUNT FOR THE MATERIAL YOU ARE fiber glassing OVER SUCKING UP MORE RESIN.

HERE IS A MORE HELPFUL TABLE FOR FIBERGLASS CLOTH

(NOT CHOPPED STRAND MAT) 1 GALLON OF RESIN WETS OUT;

1.5 ounce cloth…(not chopped strand mat).1 gallon wets out 40 square yards

2.5 ounce cloth….1 gallon wets out 25 square yards

4 ounce cloth……1 gallon wets out 15 square yards

6 ounce cloth……1 gallon wets out 10 square yards

10 ounce cloth…..1 gallon wets out 6.5 square yards

18 oz woven roving …1 gallon wets out 4.5 square yards

24 oz woven roving .1 gallon wets out 3.5 square yards.

Biaxial mat 1708.………….. 1 gallon wets out 4 square yard

 

[Chris51280]

Should almost make that a sticky. I was looking for this as well when I started to see how much resin I would need. After researching various websites, I found the same things and cross compared them.

 

[JASinIL2006]

For me, the question was more like, how much mixed resin can I use before it starts to kick off? I always preferred to stop and mix more resin than to waste a bunch because it kicked before I could use it all.

 

[NatedoggAZ]

Well, now I have an idea going forward how much resin I need to do small jobs.

I had an area of approximately 3.5' X 2' - so approximately 7 square feet of bare plywood.

First I coated the entire sheet in 1 covering layer of resin and let it tack up.
Then I used a layer of 1.5oz CSM.

I went through 700ml of polyurethane resin - catalyzed with 2% MEKP.

So... approximately 100ml per square foot of resin was needed to do the job for the initial coating and when using fiberglass.

 

[Woodonglass]

From what I can see, that's an excellent job of Glassin'. Based on the amount used, I'd say you're not gunna have any issues moving forward with your glass work on this restoration.:encouragement:

 

[NatedoggAZ]

Thanks Woodonglass !

That was actually my first time ever doing glass work....

I used these stir sticks I got from Wal-Mart and they worked really well in the resin mixing - thought I would share:
https://www.walmart.com/ip/Go-Create-Jumbo-Craft-Sticks-75-Pack/19525319

My only real dilemma was determining if I should use expensive acetone to clean the brushes I got at the dollar store....

Other than that (besides the nasty odor - in which I am glad I got a 3M mask), it went real well.

What do you all do to grind off the excess glass around the edges? I want to be real careful to not damage the finished product...

Thanks!

ND

 

[Woodonglass]

I usually trim it off with a Razor knife but you have to do it very soon after it has Kicked. If not then you'll need to use your grinder or saw.