El Gato27

Been rehabbing a 2004 Sirrus and pretty sure I’m going to wind up keeping it. Converted it to a 1X8 and the initial test rides were really nice. Not done tweaking yet but getting close.
One thing I do not like is the paint, faded white paint with stains, some bubbling, big old LBS sticker. Doing some reading it looks like sanding is not recommended because I might gouge the aluminum. Was wondering which chemical stripper to use on the aluminum frame?

Thank you.

PS, I called a couple of powder coating places and prices start at 200+, a bit more than I want to spend.

pressed001

I had the paint on my aluminum 95 GT Tempest removed by a local bike shop. They send the frames to another firm which I believe utilizes a low temperature fluidized bed scrubber. Key here is low temp as high temps will ruin the heat treating of the aluminum if there was any. Cost me 40 bucks.

Regretfully I can't suggest any chemical strippers for you.

HillRider

Use an "Aircraft" stripper since most airlines have an aluminum skin and it will be safe for your bike. Do NOT use any caustic (lye, sodium hydroxide, potassium hydroxide, etc.) based strippers ever. Also, for those with bonded aluminum frames (Trek 1100, 1400, and similar) be vary careful if you strip them as many otherwise safe stripper can attack the bonded joints.

El Gato27

I was thinking of using this rust-o-leum stripper. Supposedly good on aluminum. Frame is not bonded.

base2 

I don't know about "aircraft" stripper, I work in a different area of aviation & have never seen the stuff. However I 100% agree with the comment on caustic or alkaline lye type strippers. Those are only suitable for momentary use on already otherwise "bare" parts & even then only if the solution is weak. The soak time on a painted surface of a concentration thats strong enough to hurt the paint is probably not a great idea. For use to eat away & neutralize corrosion with a good solid freshwater rinse would be ok if it was a moderatly weak solution say under 4% or so. I think the real problem is the basivity enough to hurt paint is catastrophic to the substrate.

AtNjineer

AtNjineer

HillRider

The Jasco product illustrated above is a Methylene Chloride/Methanol mix and should be safe for welded (not bonded) aluminum frames but is VERY hazardous for skin contact and inhalation. If you use it follow the label precautions and always work outside or in a very heavily ventilated work space.

sch

To reinforce Hillrider, after looking at the MSDS for Rustoleum Aircraft remover, it is the same as the Jasco: ie safe for aluminum but extremely toxic if ingested,
moderately toxic for inhalation and topical exposure. Must be used outdoors, preferably with gloves, a fan and best with an organic vapor rated inhaler.
Methylene chloride and methanol are both heavier than air as vapors and can result in carbon monoxide poisoning at the mild end of their toxicity range.
Would I use them, yes but with precautions and suspect I would not want to strip a whole frame with them.

As to heat treatment of aluminum, it should be noted that the usual manufacturing end approach is to bake the welded frame at ~900°F for an hour.
From that POV powder coat oven temps and time frames will not affect the frame significantly. Powder coating is done at 375-400° F range where
fluidized bed stripping is upwards of 800° F, which is definitely too hot for any conceivable bike frame, metallic or otherwise.

El Gato27

Stopped by the Depot on the way home yesterday, they don't carry the Rust-O-leum product. They carry the Klean-Strip Premium Stripper. Active ingredient is also Methylene Chloride.
Every article I read has the same precautionary warnings. Will have to get a respirator.
Or use the organic stripper--CITISTRIP, supposedly works but much slower.

pdlamb

Personally, I'd just do it outside on a cool day (preferably below 70-75F), and skip the respirator. I would, however, suggest getting some gloves. You may have to read up on which kind of gloves protect against methylene chloride -- some rubber gloves don't, but I don't remember which kind does.

DrIsotope

Kleen Strip Strip X. Water based, works a treat. Just say no to Aircraft Remover, unless you have a really stubborn finish (which a bike won't have.)

Brushed on the Strip X with a chip brush, and this was about 5 minutes later:



The whole frame took a single application, washed it, then spot treated the welds to get the last of the stubborn paint off. While you're buying the Strip X, get a can of Kleen Strip After Wash. It is amazing. Leaves an absolutely smooth finish for priming.

HillRider

Kleen Strip Strip-X is not water based, it is the same Methylene Chloride/Methanol base as the other strippers recommended above and requires the same handling and ventilation precautions. If you look at the MSDS's (Material Safety Data Sheets) for all three products, they are nearly identical.

02Giant 

There are mentions of using gloves, safety glasses/goggles is a must also.

DrIsotope

I should have said, "cleans up with water." It's not even on the same planet as Aircraft Remover. I've gotten way more than my fair share of chemical burns from Aircraft Remover. Strip X is practically gentle, as far as paint strippers are concerned.

"Nearly identical MSDS sheets" is meaningless. Simple Green and Purple Power are different in only a single ingredient. Simple Green has an almost pleasant odor. Purple Power makes everyone in the room start coughing as soon as it's uncapped.

I've used Strip X-- a lot. I've used Aircraft Remover-- a lot. As well as White Lightning, Easy-Off, and most any other household product you can think of used to strip one thing off of another thing. Muc-Off Chain Degreaser is 10x worse than Strip X. As it says on the bottle, "can defat skin." Fun!

pressed001

Thank you for the detailed answer. My frame is Al-7005 and I am now more curious than ever to know exactly how they removed its paint. They described the process which sounded to me like fluidized scrubbing. If this is correct and they did use this method, I believe that 7005 would undergo serious changes at 800°F and would be compromised unless tempered again. The bike is by far my current favorite and seems to me to be very stiff. It seems also to be quite robust so far. But I am by no means a down-hill or BMX cyclist.

This whole topic is of such interest to me because I have just purchased a steel Ritchey Timberwolf and do not like the color. Therefore I am searching for paint removal options. Having the paint removed by the same bike shop is a possibility. But first I need to know if their process is OK for HQ steel. I will call them tomorrow..

pressed001

I checked with the bike shop and they just did a standard sand blasting on the frame and no high-temp processes.

HillRider

I hope it wasn't really "sand" blasting but a much milder abrasive. Your frame has very thin wall tubes and true sand blasting can remove enough metal to seriously weaken it.

pressed001

Good point. I will ask what they use exactly. This is a very reputable bike shop though and I am sure that they use the appropriate medium.