Xylene = Additive F?

Been doing a bit of reading on the internet.  Seems like Additive F is mostly (85%?) xylene.  Some of the info I read implied xylene only would serve the same purpose as Additive F for epoxy work.  Shopped around and found a gallon of xylene at Lowes for $18.98.  Can this xylene be used instead of Additive F?


There is a recipe somewhere in the archives.

I think HerbSpitzer posted it up.

IIRC, additive F is xlene and wax.

Any idea what type of wax?

Will see if I can dig up Herb’s recipe.  If somebody has a link, pleas post…

Add F has some extra ingredients you won't get if you try to mix your own. Or you can do a whole bunch of testing like RR did and come up with your own recipe.

File this under what it is worth, since I only use Fiberglass Hawaii epoxy, which has a similar surfacing agent.

If the board is clean enough, and the epoxy is warm and free of contaminates, or crusty dried epoxy stuck on the lip of the jug, skip the additive all together.

If you are doing a hotcoat with surfacing agent, and then do a finish coat over that, you will see a white separation line between the two coats. 

Meaning if you sand through the finish coat, and touch the hot coat, the wax layer will show as a white line. looks nbad it the board is tinted.

Stingray has his bare hands wiped on the back of his tee shirt method for removing dust; I like the vacuum with a brush attachment, then drag cheap colored masking tape ( not the 233, but green from home depot) until the tape stops turning white with dust.

Xylene is a medium to carry the wax in solution, but xylene greatly lowers the strength of the epoxy.  Better off thining with heat.  But only heat what you use.  Heat and cool cycling will make the epoxy clump up like curds in milk.  Throw it away or just use it for fin boxes at that point.

Hope that helps

Useful input gents.  Thanks.  Just hoping xylene alone would work, to avoid this crust I get on my additive F (container lid tightly sealed).

Still curious about Herb’s recipe just the same.  Couldn’t find it though.

Don’t doubt RR has a lot of trial and error tied in up Additive F.  But this crust is a pain in the ass.

I don’t about hurting the strength, on an entire hotcoat or lamination I only use at most 3-4 CC’s, enough to make sanding easier, more is not always better

Add F is great for easier sanding and getting consistent results when temperature changes etc.

Xylene may weaken epoxy, but at 1% or so, in the top coat(s), is that a big deal? I doubt it.

The crust that forms on your Add F, is mainly the stuff that makes it work well!

Otherwise, you certainly can add a few drops of DNA or xylene to thin your mix very slightly…

But just  thinning won’t help as much with flow, sanding etc. as Add F, especially if the temp. dips below 70 F.

I feel like I get more of the little dust spots without it also, I am not very good at dusting.

Thanks Herb.

Anybody know if a specific type of parafin is needed?   Canning, bees wax…?





Always shake the hell out of it before you use it.  That will make any wax disolve again.  Also warm under hot water if its cold.

Greg Loehr has stated repeatedly here that it is NOT wax mixed with Xylene.  I believe him.

whats the best way people have found to dispense there ADD-F ? bit annoying having to seal it up all the time an when its crusty its not easy to measure!

Hello BG Surfer....

You are a smart guy. Smart guys tend to overthink the process. AddF is a "sanding" agent. It is not a "thinner". I use less than 1/2 the amount of F recomended on the can. I always use AddF on Lams and Hotcoats and Gloss coats. I strain my F. If the liquid is clear it's good to use.......Tons of crust on the top of every can of add F I have ever owned. 20 bucks for a pint....and that pint will go a long way

Mark Miller is a great guy.....his boards are stronger...mine look better....HaHahahahahahaha :)


Hahahahahahahaha,  Just wait till next year = )

Thanks for the input Ray.  Not looking to thin.  Just want a surface agent for sanding.  I use little each year for small projects.  I live in the middle of rural nowhere.  Shipping is a killer.  Got plenty of Xylene and paraffin around.

Mike and John, not looking to challenge Greg Loehr.  I bought his epoxy video a couple of years back, very useful.  I respect and use his product.

I like to experiment a lot.  If the xylene + paraffin home-brew will serve the same function as additive F reasonably well, that would be great.  Many of my projects are for developing build techniques and designs.  I don’t need a pro retail finish, just need it to sand a little better.

A gallon of Xylene cost me $20 at Lowes. I can get some Gulf Wax at Walmart for $5.  If it works, $25 will let me do a lot of experimental/research builds.  If it doesn’t work, I’m only out what it would cost for 16 oz of Add-F + shipping.  If nothing else, I can use the xylene to replace any evaporation from my crusted over Add-F bottle.

I always value the input I get at Sways.  Lots of talented folks here.  I consider everybody’s suggestions before trying something.  And I read a lot.

I appreciate the advice offered and technical information received.  Lots of skilled people here willing to share their expertise.

Mahalo & Peaceful New Year.

I was not aware of that… I’m sure you and he are right.

Missed your comment/question Jb.

I have been using syringes, 5 ml (cc) for small batches and up to 60 cc for larger batches – but I noticed xylene (might be the acetone I use to clean them) is dissolving the graduated markings especially on the small syringes.

I just punched through the crust and sucked out the liquid below (apparently xylene only).  My last hotcoat looked like it had a bit of amine blush.  From what I have learned here at sways, I probably need to warm and mix my Add-F a bit before use, maybe add a few ml of xylene.

I plan to try calibrated glass pipettes (got plenty at work) for small batches, with a thumb pump.  Afraid the xylene/ acetone may dissolve the graduated marks on the pipettes too though.  Only one way to find out.  If it’s the acetone that’s removing the marks, I can fix that problem.

I use a simple plastic graduated cylinder, with molded calibration marks instead of paint or whatever.

I like the graduated cylinder idea.  I have a couple like yours.  

The advantage of syringes and pipettes is that I don’t have to pour anything.  Very handy when only a few cc are needed for mixing small amounts of epoxy.  Pretty sure it was the acetone that removed the painted calibrations.

Just checked my Add-F bottle again today, completely solid now.  I guess tightly sealed isn’t tight enough for a solvent with a flash point of 86 F.

I shake the can, pour out a small amount into the lid and eyeball what I want in to the batch, if it is solidified in the can, it is too cold, put it in a pot of hot water. I watched Kevin at Channin use styrene based surfing agent in epoxy