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Some tips for using epoxy

Started by Brad_bb, February 16, 2017, 04:30:45 PM

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Brad_bb

I'm no expert, but I've been using West Systems Epoxy for more than a year now and here's what I've learned. I haven't gotten into the colored or fluorescent stuff yet...Just clear so far.

1. I use the green 3m automotive masking tape.  It works pretty well.  It's all about the adhesive.  I'll say that it's not perfect as occasionally I'll get a leak.  Actually I should try to find an even stronger adhesive.  Automotive is strong but designed to be removed and not leave residue.  The stronger you get, the more likely to leave residue.  That's probably ok for the wood cause we'll be sanding anyway. 
2. If you have a check that goes to the end of the timber you need to block it so it can't run out the end.  Cut the end so you have a smooth surface to tape to. If you have a rough chain sawed type surface, your tape won't seal properly.  Sometimes I'll pack the end of the check with paper towel bits and then tape the end thoroughly.  I'll have left enough board length knowing that I will have some paper towel in the end and will need to trim it off. 
3.  Also when you are taping a vertical surface, start at the bottom with first piece of tape and work up.  I've had more success that way. 
4.  If you are filling a large void or an end check, start using a fast hardener and only use  enough mixed epoxy to seal up the bottom of the void or the end of the check.  The goal is to seal up the places there epoxy would run out had you just decided to fill the void in one shot.  You're creating a sealing coat.
5.  When filling a large void, use a slower hardener.  Using a fast hardener will make the chemical hardening reaction happen quickly and generate a lot of heat.  This can create gas bubbles and cloudiness in the epoxy.  You want a slow reacting hardener.  You'll also have better luck filling large voids a little at at a time.  I probably fill 1/8-1/4 inch thick at a time to reduce heat build up.  A little fan to help take some of the generated heat away can help in some situations.  If you're in a hurry you can sometimes fill a lot of material at once with a very slow hardener.  You are taking some risk though that it could react to generate heat and cause cloudiness.
6. You can usually sand after 12 hours although they say 24 is full cure ( on west systems brand).  The quick way to remove excess hardened epoxy is with a belt sander with 50-80 grit.  If you're not used to a belt sander you always have to keep it moving so it doesn't remove too much material in one spot.  You let it's weight do the work.  You just float it on the surface either back and forth or in an elliptical pattern.
7. After sanding epoxy, it's no problem to add more if the void wasn't filled completely or if you have some pits from air bubbles.
8. Air bubbles will form in the epoxy from trapped air in the void.  So you can't just pour your epoxy and leave.  These bubbles will quickly rise to the surface. You have to pop them and the best way is with a mapp or propane torch.  You just kiss them with a quick pass with the flame and  it heats the  bubble surface enough to reduce the surface tension and pop the bubble.  Imparting a little heat to surface epoxy in cooler weather will help it liquify and spread out.  Be careful though, as too much heat will accelerate the hardening reaction and can burn the epoxy in place.  Just wave the flame by quickly to impart just a little heat.
Anything someone can design, I can sure figure out how to fix!
If I say it\\\\\\\'s going to take so long, multiply that by at least 3!

Larry

Got pictures?  We like pictures. :)

This is my tip.  Thinning Epoxy  When one wants to make sure it gets in the smallest crack.  I've been using the heat method with good results.  Warm the wood with a heat gun.

Larry, making useful and beautiful things out of the most environmental friendly material on the planet.

We need to insure our customers understand the importance of our craft.

Kbeitz

If you look it up you will find that it's the carbon dioxide that come from
your torch that breaks your bubbles and not the heat.
I use a hot melt glue gun the seal small holes before I use the epoxy.
I found out the hard way not to let the heat from the torch stay to long
in one spot. You got to work real fast and trying to fix a Boo Boo you only
have seconds. If you keep fooling with it you will only make it worse.
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

samandothers

Good information here for those of us un educated in the ways of epoxy!

Darrel

Thanks Brad.

I'm no expert either so I'll just keep at it 'till I am.  :P
1992 LT40HD

If I don't pick myself up by my own bootstraps, nobody else will.

Ljohnsaw

Larry,
Thanks for that link on thinning.  Very informative and something to keep in mind.

Darrel,
Is your other brother, Darrel around?  (Sorry, couldn't resist - I'm a Bob Newhart fan)
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Ford 545D FEL, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 42" capacity/36" cut Bandmill up to 54' long - using it all to build a timber frame cabin.

Darrel

No IJohn, but years ago my wife and I did foster care and at one point we had two 2 year olds both named Daryl.
1992 LT40HD

If I don't pick myself up by my own bootstraps, nobody else will.

RPF2509

Right about the CO2 to pop bubbles.  On small projects I just breath on the surface and it clears the bubbles right away.  Ones that come from pores in the wood are different and best prevented by a thin sealer coat. If no sealer be alert with a pin or toothpick and don't put the wood in a warm room after pouring (makes the air expand and bubble out).

Brad_bb

Depending on what is used as a sealer makes me wonder if the epoxy will bond well to the sealer?

When it comes to thinning epoxy, which I have not done yet, I was planning to try the following water thin epoxy that Matt Cremona on Youtube was using for an outdoor farm table.  I haven't purchased this stuff yet, but am planning to.
https://star-distributing.com/store/Clear%20Penetrating%20Epoxy%20Sealer.html
Anything someone can design, I can sure figure out how to fix!
If I say it\\\\\\\'s going to take so long, multiply that by at least 3!

RPF2509

I just use the same epoxy with no thinning for the sealer as the final coat.  I spread it thin with a popsicle stick.  I've had good results both sanding the sealer and not sanding - depends on the roughness of the original piece.  Never had a problem with the second coat not sticking.  I've used Enviro-tex epoxy almost exclusively - its designed to pour on a very thick coat but that thin first coat sure helps with the air bubbles from porous wood.

tule peak timber

Quote from: Brad_bb on February 26, 2017, 12:35:58 PM
Depending on what is used as a sealer makes me wonder if the epoxy will bond well to the sealer?

When it comes to thinning epoxy, which I have not done yet, I was planning to try the following water thin epoxy that Matt Cremona on Youtube was using for an outdoor farm table.  I haven't purchased this stuff yet, but am planning to.
https://star-distributing.com/store/Clear%20Penetrating%20Epoxy%20Sealer.html
Yes it will, but it truly is designed as a penetrating agent on punky or dry rotted woods. Very useful  for bark on projects too.  Rob
persistence personified - never let up , never let down

knowslittle

  Just a tip. I've used a lot of West Systems, perhaps 100 gallons or more, but be careful when sanding. I may be wrong, but as I recall although it dries hard fairly quickly, it can take up to 9 days to cure, and if sanding the uncured dust can travel into your lungs and eyes, and onto the skin, where it does cure.
Probably not good.

BTW- Gougen Bros, (West systems) is a super resource, their technicians are dedicated and are the best.

bob

tule peak timber

persistence personified - never let up , never let down

Just Me

Quote from: knowslittle on February 27, 2017, 09:40:17 PM
  Just a tip. I've used a lot of West Systems, perhaps 100 gallons or more, but be careful when sanding. I may be wrong, but as I recall although it dries hard fairly quickly, it can take up to 9 days to cure, and if sanding the uncured dust can travel into your lungs and eyes, and onto the skin, where it does cure.
Probably not good.

BTW- Gougen Bros, (West systems) is a super resource, their technicians are dedicated and are the best.

bob

I have been using West for 30 years, they are indeed the best. Their users guide is free for a phone call and will answer questions that you did not even know you had. It is the place to start.

I have commercial doors that have been standing up to Northern Michigan weather for thirty years and are still fine, and I use West System exclusively for both construction and the base finish.

69bronco

I am also a big fan of West system products, used them in the mid 80s on my first boat and have been using ever since. One thing I'll throw in here fwiw, epoxy on its own has no resistance to U.V. and will degrade. It has to be coated with a UV inhibitor  (paint, spar varnish etc.) If your planning on exposing it to the weather. I just finished a desk that will sit in front of a large south facing window, erring on the side of caution I used spar for top coats.

tule peak timber

Photo of an ad 11 years ago put out by West Systems. Been using various epoxies since the 70's. I contacted them and wasn't happy with the "salesman "who attempted to BS me and would not answer my questions. There are LOTS of other epoxy manufacturers around.  Although I still have West in the shop for particular uses, the bulk of epoxies I use come from other sources. Just a side bar.........

 
persistence personified - never let up , never let down

Larry

Like Rob, I also use epoxy from various sources.

Last year I bought some TotalBoat from Jamestown Distributors because of the price and free shipping.  They tout it is a generic with the same ingredients as name brands.  I've used it on a couple of my own outside projects and it seems just fine.

TotalBoat

Larry, making useful and beautiful things out of the most environmental friendly material on the planet.

We need to insure our customers understand the importance of our craft.

tule peak timber

Different epoxy's have different set times,handling characteristics,viscosity,temperature windows,clarity,elasticity,hardness, cost,and on and on.......Depends on what you are doing. Rob
persistence personified - never let up , never let down

Ljohnsaw

I picked up a "free" little sailboat off of CraigsList.  Definition - Boat, a hole in the water into which you pour money. :D  I need to apply a coat of epoxy to the upper part of the mast (lower is aluminum) and make a dagger board and rudder (coat with epoxy).  A friend recommended that I make two dagger boards - one for sailing and a short one for fishing when I want to paddle/row or add a trolling motor.

I came back to this thread looking at the recommendations and techniques.  After reading lots of review and tips elsewhere, it appears that I can use West Systems or Total Boat with equal results.  The only "complaint" with TB is the slow set is pretty darn slow.

Looking at my local store (West Marine), Amazon and JD, I compiled the following prices.  It was well noted to purchase the pumps to insure that mix is proper every time.  I did find a "kit" from TB on Amazon that included the pumps (plus 2 mixing cups, wood mixers and gloves) at a great price.  So I added pumps to each of the other sets I made up.  Note that the quart and gallon sizes would be for both parts mixed together.  That is, a gallon of resin is not a full gallon until the hardener is added.  Also, it looks like all have free shipping.

So just for reference (as of March 2017):

($qt/$gal)   
                       West Systems                  Total Boat
West Marine          $90/167  + tax                   N/A
Amazon                $83/150                          $64/141
JD                        $69/141                          $64/136
Amazon Kit              N/A                              $50/120
JD Kit                   NA/$153                          $50/120

Note that a gallon price is just a little over twice the quart price - so incentive to buy more!  I'm thinking that a quart would probably not be enough so buying a gallon will be the way to go.  I was concerned about how long of a shelf life the product has and I read about 6 months but one guy had it over a year.

I'm also considering making my kitchen sink at the cabin from wood and using epoxy to seal it up.  I will have slab counter tops and will most definitely be using epoxy there.  I guess I'll be trying a gallon of Total Boat from JD (kit).
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Ford 545D FEL, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 42" capacity/36" cut Bandmill up to 54' long - using it all to build a timber frame cabin.

Don P

I had a partially used gallon of abatron epoxy left from a restoration job and had stuck it in the barn and forgotten about it. 10 years later a homeowner wanted to try to save a window so I dug it out and tried a test batch, amazed me it still worked.
Several years ago I was looking for a food grade epoxy thinking of making wooden buckets and beer steins and read somewhere that once it has kicked they are all a food grade plastic. I only had to make and sell a few buckets before it became apparent it was a quicker way to go broke than farming  :D.

tule peak timber

Ljohnsaw, Make sure you top coat your exterior epoxy with one of several uv resistant poly's/varnishes available . Some are better than others.Price wise , take a look at Aeromarine 300/21 series.  Rob
persistence personified - never let up , never let down

samandothers

I was rereading this thread and have some questions related to coating an old washstand top prior to attacking a vessel sink.  Both @tule peak timber and @Larry made comments that certain epoxy works better for different jobs.  I have some questions below.

I was looking at using 'TotalBoat Table Top Epoxy'. Which product would y'all suggest?

My plans are to strip the top, I am not sure of the finish.  It is not real shinny.  I do not think it is wax but rather just oil or oil and poly. Will epoxy adhere without stripping?

If I need to strip it and desire to stain, can a stain be applied under the epoxy?

When I attach the vessel sink I plan to use an adhesive to hold it in place as it will sit on top of the washstand versus set in the top.  Will an adhesive stick to the epoxy or do I need to sand down to the wood through the epoxy or tape the area off?

I know there are several questions there, but inquiring minds want to know?

Thanks folks,
Sam

Larry

I've not used Total Boat Table Top Epoxy, but based on results from some of their other products I would try it.

I would be afraid to apply epoxy over any other finish without testing and/or positive information from the manufacture.  That might be one of those questions the manufacture would give a "No" answer just to stay on the safe side.  It would be worth a call in any case.

Sorry, that I couldn't give a better answer.

Larry, making useful and beautiful things out of the most environmental friendly material on the planet.

We need to insure our customers understand the importance of our craft.

samandothers

Thanks Larry for the input.  I thought you may have tried this epoxy or might suggest a different product.  

I may contact the manufacturer about putting it on top of oil.  I am not sure if it will look right if it is just applied over the stripped wood.  

btulloh

I haven't done epoxy over oil but shellac will generally go over anything and anything can be put over shellac.  Shellac is a miracle substance and is indespensible in finishing work. 
HM126

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