Dope thinner = isopropyl alcohol?

You're referring to what we call denatured alcohol here in the states. I don't know what they call it elsewhere, but it's ethyl with just enough methanol in it to make it nontaxable under the liquor laws, and you buy it in hardware stores. The product usually called rubbing alcohol is in fact isopropyl.

| > Rubbing alcohol is 30% distilled water and 70% isopropyl alcohol. Not | > suitable for a dope thinner. | >

| No, its ethyl alcohol and a little methanol. | | Water content is varaible.

Strange! The percentages and content I posted were from the label of a bottle that I purchased at the drug store. I guess they don't know what's in their product.

The only product you use with butyrate is lacquer thinner, because butyrate is a lacquer as well as nitrate dope. In fact you can use the same thinner on either, though it may take more thinner with butyrate. You can also use acrylic lacquer for your models which actually works better than butyrate, at least if fills faster. A lscquer is any paint which is simply a plastic product melted with a solvent and only requires air drying of the solvent to dry. There is no curing. Enamals requrie some type of curing or bonding where some chemical change is taking place. They need special thinners or reducers which do not have chemicals which may change or retard the curing reaction.

Some thinners have alcohol to absorb water to help prevent initial blushing. Only so much methanol can be used as too much will cause the resin to lump but methanol absorbs water better so sometimes they have both methanol and isopropyl. Pure isopropyl is more expensive than methanol as well. Thinners have chemicals which promote rapid drying for primers, or products which slow down drying for an extra glossy finish. Products made for the summer, winter, etc. If using automotive thinner for dope tell the store what you are doing and they should be able to get you what you need.

Then there was Aerogloss dope. It did not conform to standard butyrate specs, if I recall correctly. Aerogloss and Testors were my favorites. Testors seemed less fussy regarding thinner. Trying to mix the two finishes on a model could be tricky.

Ed Cregger

Yeah?

Oh well. I thought denatured alcohol=surgical spirits=rubbing alcohol= methylated spirits, with the only oddity being here in te UK it has aniline to make it purple...when sold as 'meths'

Isopropyl alcohol is sold as 'screen cleaner' and 'car washer antifreeze :-)

Advanced warning: nothing here about modeling.

1. "Denatured Alcohol", in the US, is rather ill-defined. I spent a week earlier in the summer trying to find the best denatured alcohol for an old alcohol stove on a boat. I bought five or 6 kinds, tested each, and checked the MSDS. The amounts of methanol ranged from 5% to

60% (yeah, 60, not 6!). The amounts of ethanol ranged from 90% down to 30%. And there was other crap mixed in, because it's too easy to do fractional distillation of eth/meth mixes and get out just the ethanol, at which point the stuff can be sold for a great deal more, etc. The best stuff (for a pressurized alcohol stove) turned out to be about 90% ethanol, but burned quite bright green because of some additive, and left a nasty blue-green residue on stuff :-(.

1. "Rubbing Alcohol" is similarly under-defined. But MOST of what's sold in drugstores is "Isopropyl Rubbing Alcohol," which is typically somewhere around 70% isopropyl, 30% water. But that's not a standard at all, and you should check the bottle to see what you're getting.

--John Hughes

Ed your suspicions are NOT correct. Dope thinner is dope thinner. Not Alcohol. If you have Aero Gloss "dope" stick with Aero Gloss products. It never worked with anything and that has not changed over the years with EPA noses stuck into citizen'e private business.

As for others, both Nitrate Dope (not "fuel proof" for nitro / alcohol fuels) and Butyrate Dope (for the nitro fuels) are available. the best suppliers in the hobby industry are SIG (repackaged Randopph Aircraft Supply's dope) ane Brodak, also a Randolph product, but one vastly improved over the regular stuff. Brodak is top stuff.

Acetone, Lacquer Thinner, and MEK will thin both Nitrate and Butyrate dopes. They are fast drying and thus will induce a condition called "Blush" a whitish streaking discoloration, especially in situations where the humidity is above 50% humidity and/or warm air.

The use of regular Dope-Thinner will help prevent such condition. Both SIG and Brodak supply a kind of thinner called "Reducer". This can be taliored to conditions, will slow the drying processes and virtually eliminate blush. Almost a necessity unless you are in direct sun-light HOT air and humidity well below 50%.

For a rubber powered machine, several very very thin coats of nitrate will suffice. For those hand-rubbed 25 coats, try Brodak. If you want the most professional finish possible, ask Lyman Slack, posted above. He is the miracle worker with finishes. (;-))<

Wow, thanks for all of the replies! This thread is WAAAAAAY more informative than I'd imagined it would turn out to be.

I, in fact, bought a one ounce jar of Midwest Aero Gloss clear and a one ounce jar of Midwest Aero Gloss thinner. The thinner is labled as containing methal isobutyl ketone. Since my local Hobbytown USA tagged me for about $3.99 per one ounce jar (29.5ml), I just wanted to make sure I wasn't being suckered and there might be a far cheaper alternative.

Thanks again for all of the replies.

On Mon, 27 Nov 2006 23:35:45 -0600, I said, "Pick a card, any card" and "Ed Paasch" instead replied:

No. Dope thinner = Kevin Kline on a diet.

-- Ray

:-)

It sure would be easier if everything had the same name on both sides of the ocean. I thought I had just about figured out the differences in terminology, and now you tell me that they don't even use the same type of alcohol for medical purposes in both countries....

Just wait till you want ammonia to bend balsa.

In the US its 'Windex' - here its Jeyes 'Power Clean' or something.

I use plain ole ammonia. The strong stuff that will knock you out if you take a wiff.

I use plain ole ammonia. The strong stuff that will knock you out if you take a wiff.

I don't know how it is in the UK, but here you can buy a bottle of plain ammonia. A little bit goes a long way.

Yes, it is commonly sold in the cleaning supplies isle ....

On Tue, 05 Dec 2006 18:00:11 GMT, I said, "Pick a card, any card" and "Six_O'Clock_High" > ammonia. A little bit goes a long way.

There's a small island for ammonia? Who would have guessed?

-- Ray

Awwww.... Typo...aisle

Who would have known if it were not for your discerning eye?

Most folks use *in* an aisle when speaking of a market (grocery store, super market, etc.) and *on* an isle when speaking of a chunk of land surrounded by water. Guess...