Pickling

[ron]

Hi All
I have seen many references in books to pickling after silver soldering something, but they never state how long to leave it in the pickle, I'm using fresh battery acid and am curious as to how long I should leave it in?
Ron

[jgb7573]

Not long! fresh battery acid is about 37% sulphuric acid. I use about 10% sulphuric acid and generally leave copper/brass/gunmetal/bronze silver soldered assemblies for 5 to 10 minutes and that works fine.

[steammadman]

yeah battery acid should be watered down to at the srongest 10% volume
and dont leave your boiler in too long,you will soon see when the copper
is clean,then don't foget to give it a good bath in clean water, after which
give it a dip in "clear", the dish washer additive , that will get rid of any
grease that might be left.
GOOD LUCK with your boiler making
good to see someone who is willing to have a go, instead of throwing
hard earned cash around. A true MODEL ENGINEER .
And not a cheque book engineer. (too many of them around these days)

[greasemonkey]

Hi All
I read somewhere and have been told it myself not to use used car battey acid make sure its new. The disolved lead in old battery acid can contanimate the copper and cause problems.

Andy

[greasemonkey]

Hi Steammadman
Dont knock cheque book engineers! In case you hadnt noticed engineering is dyeing in this country and not everyone has the skills neccesary to build a steam powered model. One club I was a memeber of was split 50/50 between 'model engineers' and 'cheque book' enginners. Those who didnt have the skills to build models often had other skills that were useful to the club, but without them the club wouldnt have existed! These cheque book enginners you seem to disaprove of may have engines that they use to give rides to the public and help raise funds for the club to proviide facilities that I am sure you also benefit from.
Buiding a boiler is no small task and also very expensive to get wrong! I personally have a foot in both camps and I'm not ashamed of it. I bought my Nigel Gresley as something to play with whilst I build 'my' engine, but it has helped generate useful income for the club all the same.
Having a full time job and a young family means my workshop time is limited and if I can use my cheque book to help speed up the process with items like laser cut frames then great. Somehow the younger generation needs to be encouraged to get involved in what is a fantastic hobby, but predudices against people without the skills will only serve to keep them away.
Rant over, back to the workshop! Ive got two 'David Hudson style' driving trolleys to build and for the benefit of the cheque book engineers, yes, one will be for sale.

regards

Andy

[chris vine]

Hi Ron,

there is a drain cleaner which you can buy in a proper plumber's merchants. It is 90 odd% pure sulphuric acid. Very dangerous. You must add the acid to the water (if you do it the other way round the acid will spit as the water is added) about 5 or 10 % strength will do fine.

The only reason for suggesting using this rather than the safer battery acid is that I found it difficult to get hold of.

Good luck with the boiler....!
Chris.

[SteveW]

Ron,

I bought a bottle of drain cleaner from my friendly plumbers merchants a while back. It's a bit grey and very blobby and with a high sulphuric acid content. It's still on the shelf in the garage.

I tend to use citric acid from the wine kit suppliers. It's also quite good at pre-cleaning prior to soldering.

A word of caution: Someone at the club had a nearly completed boiler marinaded in sulphuric acid. Unfortunately the copper boiler included a steel bracket (don't ask). The copper faired OK but the steel nearly disappeared completely.

[ron]

Thanks for the replies, so far I haven't had any problems with battery strength acid [new] leaving brass parts in it for up to half an hour but I'll do as suggested and dilute it to 10%, at 37% it is rather good at finding nicks and cuts on the fingers!! and leave things in it for a shorter spell.
I had no bother buying battery acid, got a litre from my local autoshop, bit annoying having to buy it though, used to work for the company that made it but the plant shut down in the late 80s.
As regards cheque book engineers, I have long been involved in classic car restoration and the same problems re 'real restorers' and 'cheque book restorers' occurs, I am very much in the first camp but I think we should embrace anyone who makes a contribution to our hobby, particularly as the enthusiasts for these engineering based hobbies are mainly middle aged men, we need to attract younger people who maybe don't have the skills/time available but might develop them in time.
Ron