In yesterday’s post about Bench Dog silicone glue brushes, a couple of readers mentioned how they use acid brushes. I remember a time when I had no ideas what these were, and so a short intro post was definitely in order.
An acid brush is a small disposable multi-purpose brush. I believe they got their name from the plumbing industry, where they were used to apply acid flux for pipe soldering applications. Please correct me if I’m wrong.
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Acid brushes are small, they’re plentiful, and they’re cheap. You can sometimes buy them individually, but more often you’ll find them in packages of 5, 12, 100, and so forth.
They often have small bundles of horsehair or nylon bristles, and metal tubular handles.
You can use an acid brush to apply glue, or other liquids and [certain] chemicals, and for quick small-area cleaning or wiping applications. They sometimes leave a bristle or two behind – just keep that in mind.
You can buy these in multiple sizes and lengths. A ballpark estimate is $0.35 each. Although disposable, you can sometimes get multiple uses out of each brush, depending on what you’re using them for.
Buy Now(via Amazon)
If you’ve used acid brushes or similar, what type of work do you put them through?
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And where’s a good place to buy these? I linked to Amazon because they have a lot of options, but I don’t remember where I bought mine from. Maybe from an industrial supplier? I once bought a pack of 5, and am currently still working through a bulk pack from a few years ago.
John
This is one of the few things I buy at Harbor Freight. I jokingly have a rule there which is I only buy stuff from there that likely wont kill me, ie disposibles/consumables no spinny blades and death tools as I’ve had terrible luck with their power tools quality. At any rate, they have 36 long 6 inch handles (normally I’ve only seen the short 3 inch ones) for about $3:
http://www.harborfreight.com/36-pc-12-in-horsehair-bristle-acid-shop-brushes-61880.html
I use these all the time from applying glues to also drilling and tapping oils as well as their original purpose of adding fluxes. I use them all the time in my mills and drill presses as mentioned for applying cutting and drilling oils and cleaning away the metal debris. Works fairly well and if i loose one, they break, well I got a load left.
Mr. X
Good post!
My Rules for Harbor Freight:
OK to buy if the product:
1. Does not require electricity.
2. Has no moving parts.
3. Does not require any precision.
Chris
Sean
1- What does the numbering mean in ref to acid brushes ? Ie 6” long #2 horse hair acid brush. What’s the #2 stand for ?
2- allot of crap quality a-brushes on amazon ( found out the hard way ). So does anyone have experience as to where to find a nice densely packed acid brush in ⅝” to ¾” width bristle head ? 12/1/22
Stuart
Numbers usually refer to brush head size, in this case maybe similar to art paintbrushes?
Jerry
Plumbing supply places will sometimes have them in bulk packs. If you are needing, say, 10 or less at a time, check places like Home Depot because the shipping on small amounts is often more than the brushes.
I use them for applying flux to solder joints, and as chip brushes, to clean little nooks and crannies of things I can’t or don’t want to use compressed air on. I do not use them with glue, as the few time I tried it, they were shedding bristles. I would much rather use a piece of lint-free rag for a disposable one-time use, than an acid brush for that reason.
Dave L.
At home I use them for cleaning tasks, as well as applying Naval Jelly, etc.
Nathan
some plumbing supply places (johnstone, etc) will even give them away – in small numbers.
IE walk in – they have opened bags in their shipments – placed in a bin by the register – for the guy that walks in and wants like 2 of them. please take them,
at least the place near me does this.
John Sullivan
+1 for Harbor Freight, and bonus points for John’s (above) guidelines for what to buy (and not buy) from them. A bulk box of acid brushes from there will last a hobbyist for years if kept away from humidity (the cheap metal tube can rust and flake onto your work). It’s really not worth trying to re-use one, ever.
SteveR
Like Jerry, I’ve used them to apply flux for rosin-core solder, remove chips while cutting threads and to clean taps and dies (I don’t have an air line). Whenever possible, though, I dip a lead wire into the flux, which puts just enough on it for soldering. Otherwise, it heats and runs to places I don’t want it to when I apply the tip of my soldering iron.
I put dielectric grease on lots of things electrical (including the contact ends of small batteries and light bulbs); the brush puts it just where I need it. Use one to put grease on the terminals of my car’s battery to minimize corrosion. I generally don’t use them to apply wood glue. For glue spreading, I have a small silicone food basting brush which can be cleaned and reused.
They’re great for applying greasy or caustic materials whenever you want to keep your hands free of that substance. The uses are limited only by your imagination.
Farid
We use these a lot at work for for doing PCB rework. They are great fro cleaning residual flux after soldering. The nylon ones are stiffer which is good for some cleaning jobs (e.g removing conformal coating), but I like the horse hair ones since its easier to get between pins and tight nooks . We cut the bristles down t least in half to provide some stiffness. Usual solvent is 99% Isopropyl alcohol, and others as needed to remove conformal coatings.
We also use them to apply moly. grease to stainless hardware; wax for mold release; cleaning oil and chips after machining or drilling some parts, etc.
At home, I pretty much use them the same as work. I hardly use them to apply glue. due to the stray hairs, unless it really does not matter. One very useful application I found is applying grease to the car door hinges every fall as part of car winterization.
I do find the quality varies a lot and on some of cheapest bargains, the hairs tend to pull out real easy, so they are definitely a one time use item . But, anymore even the ones we get form technical tool suppliers are very low quality. I have some in the lab that have been around for a couple of decades and the bristles are still intact.
Farid
Oops, I forgot to mention static concerns when using the nylon ones with electronics. Any way, be careful around sensitive electronics, and especially in dry weather.
Sean
I’m hoping next week is Teflon tape. 😉
Just joking, Stuart. It actually cracks me up that you somehow became interested in acid brushes enough to write a post about them.
Stuart
I’d post about self-sealing fittings before teflon tape, no joke. Maybe eventually teflon tape.
Tools and supplies that one person takes for granted might be a new problem-solver for someone else.
Remember, this is ToolGuyd, which I intended to be read as Tool Guide. If some readers learn more about acid brushes from this post, or those who use acid brushes hear about ways of using them that they didn’t think of before, then it’s a worthy topic. =)
Jerry
Instead of Teflon tape, how about a users guide to thread sealants? I just got a new can and was almost overwhelmed at all the choices: red, blue, white, Teflon, non hardening, air curing, etc. I wasn’t sure which was best for my uses so wound up getting what the salesman at the store recommended for all purpose general use, the white Teflon non hardening paste.
Sean
Actually, I did learn one very useful thing from another person’s comment: using an acid brush to apply Naval Jelly. This is great!
Lately I’ve been using it to clean up some old, rusted tools, but I was just trying to pour an appropriate sized glob directly out of the bottle onto the tool and then spread it around with a shop towel. You don’t want to get that stuff on your hands.
A brush could really force it into those crevices! (I’m thinking an old pair of Klein’s I found in my grandpa’s old tool stash.)
Yadda
I definitely need to pick up a few of these. Having a spouse that likes to do crafty things there are always a large number of foam brush applicators on hand, but there are some situations where they aren’t as useful.
fred
I looked at an old inventory list – and see that our pipe fitting supplier sold us 2 boxes of 144 (gross lots were popular back then) for $20.16 (about 7 cents each brush) in 1996. They were made in the USA by Oatey. We used them mostly for applying flux when sweating pipe – but I also used them for glue – and with the boy scouts for applying dye (as in leatherworking).
Ken
I picked up a box of them from Enco when they had free shipping. Much cheaper than I could have purchased locally. I use them for all sorts of odd jobs including gluing, fluxing, and greasing.
Penumbra
Enco! The harbor freight for machinists. I haven’t bought from or thought of that place in 10 years. Thank you for reminding me of them. Good stuff at great prices.
John G.
+1 For HB. Been using these for years!
Noah
I actually use chip brushes a lot more than acid brushes, but mostly in the same applications – glues.
ccb
3/8″ seems most common but others sizes are available http://www.gordonbrush.com/applicator-acid-brushes-acid-brushes-rolled-handle-c-1_59_65-l-en.html
KL
As mentioned in the first comment I use them exclusively for cutting oils at the lathe & mill. Get a Spill Master for your cutting oils and you’re in heaven.
fred
Thanks for the reminder about the Waco Spillmaster (their part # 3896). I thought they were no longer available (at least on Amazon) – but see that the Little Machine Shop has them. Like Menda dispensing bottles for cleaning solvent (my wife grabbed one of mine for nail polish remover) – the spillmaster is a “why didn’t I think of that” type of item.
KL
SpillMaster available at Enco
Ben
I also get mine from harbor freight. Can’t beat the price. I work at a hardware store and our cost is more than getting them at HF.
When using them to apply glue a lot of times I wish they were stiffer so I chop the length of the bristles in half with a chisel. Works great!
glenn
I usually just buy cheap disposable paint brushes. Every now and then I see them in 20 packs of assorted sizes and grab one or two packs. I use them for cleaning my power tools and for applying fibreglass resin.
Sean
Toothbrushes are MUCH better for cleaning power tools and cleaning in general. Stronger bristles certainly help.
I bought a bunch of trimmer attachment heads from a guy on Craigslist (edger, brushcutter, etc.) and went at them with a toothbrush and a bottle of dollar store cleaning solution (works SO well.) I now keep toothbrushes in every toolbag, hah.
Adam
I will use these as a detail sash brush – I’ll cut the bristles at a 45 degree angle with a scissors, and use them for cutting in paint in detail work. If I don’t like the angle, I’ll just make another….
Jim Felt
Hey there.
Next up those 3 sizes in a hundred pack from Lee Valley etc. etc. of bristle brushes with wood handles!
No? Really…
I wanna hear how someone is using them to assist Banksy or perhaps restoring abstract art pieces. Or the myriad of weird stuff I’ve done.
tajparis
They work great for applying anti-seize, and for cleaning and lubing bike and motorcycle chains.
Also handy if you saturate the bristles with paste flux, wipe off any globs, and then you can run your wire ends or component leads through the bristles to coat lightly.
SteveR
Don’t know if you saw my earlier comment about applying flux. I used to work in a concrete testing lab; one of my tasks was to apply strain gages to concrete cylinders (3×6, 6×12, 12×24, etc.). I then soldered lead wires on them to record the results from testing them to failure. My co-workers liked to use a Q-Tip, but I just dipped the wire end to be soldered in the tin of flux. I got just the amount I needed on it, and no more. You might try the “dip” method; you could save some time and not have to deal with a gloppy brush when you’re finished.
DaveZ
I use these a lot doing woodworking, but not for spreading glue (that’s what the silicone thingies are for), instead I use them to stain intricate bits and pieces like the inside corners of small boxes. Then after a quick dip in paint thinner, it’s ready to be reused again and again.
i got a pack of 50 at a local woodworking store for $10, but for those who want to give this “tool” a try and aren’t ready for such a big commitment, I’ve seen a pack of 5 at Northern Tool for just 99 cents.
Toolfreak
I’ve seen these at Lowe’s in the plumbing section with all the pipe adhesive and tape, but a less expensive option can be the arts/crafts store.
Michael’s frequently has 40-60% off one item coupons, either online or right in the in-store flyer, so a bag of these can be less than HF, or just easier to get if you don’t have a HF around.
Jon
These things can shed like crazy. Usually you only lose a few bristles, but sometimes you can lose a lot. Don’t use them for anything where shedding can ruin the project. Use them liberally where that won’t be an issue.
Andrew
I always thought they were for electroplating… The handle acts as a conductor to the plating solution on the bristles.