Working with tweed

Adam_MD

I'm finally getting round to using the tweed @martinw kindly sent me last year.  I'm covering a pedal and was looking for some advice on which contact adhesive to use and what I could use to get that lacquered look.  I saw a thread from someone a while ago who used Zinsser amber shellac which looked great but seems to only be available in the US and horrendously expensive over here.  

Nomad

You could give this a try...

http://www.ebay.co.uk/itm/Bird-Brand-Shellac-Varnish-Hard-Brown-Amber-Gloss-Finish-for-Timber-Wood-250ml-/201369616800?_trksid=p2349526.m2548.l4275

I'd be very surprised if it came out much different from the Zinsser, if at all. I have some of the latter, and could bottle some up, but I suspect the postage will get rather close to cost of the Bird Brand version. There's also shelf life to consider - shellac apparently doesn't last forever and can end up never drying properly (somewhat sticky finish). The Zinsser I have is potentially quite old now, although it seemed to dry okay when I tested it recently. But it's hard to say how much longer it would last.

Another option is to make up your own using brown shellac flakes and a solvent (the 'amber' or golden flakes are bleached and are used for clear shellac in general woodwork). Solvent is usually methylated spirits, but bio-ethanol from the local DIY works fine for me (for cleaning brushes). (Methylated spirits is mostly ethanol, with some added methanol.) However, the cost of the flakes and the solvent would easily be more than the 250ml bottle above, and you'd have loads of it - maybe worth doing if you want a litre, but the coverage is pretty nuts (even 250ml would do lots of pedals). Mind you, you'll need some solvent for brush cleaning anyway, and you may want to have some for diluting to get a lighter coat (I did this with the Zinsser on a tweed guitar case, but there was hardly any difference - I'll be trying an undiluted coat on top when I get a moment).

This is two coats straight out of the tin...

Before
http://imgur.com/Sawn4wk.jpg

After
http://imgur.com/fuA6uEP.jpg

The stuff dries very quickly, and you have to keep a wet edge going to avoid things looking patchy. On the second coat, I was applying the freshly dipped (and thus more wet) brush on the areas that were a bit light after the first cost to get a more even finish.

richalderandash

Not my thread but thanks @Nomad ! I've been experimenting with normal furniture varnish on herringbone tweed, and it comes out quite well after 4 coats.  But to have proper shellac available in the UK for a decent price will be brilliant.

Nomad

richalderandash said:

Not my thread but thanks @Nomad ! I've been experimenting with normal furniture varnish on herringbone tweed, and it comes out quite well after 4 coats.  But to have proper shellac available in the UK for a decent price will be brilliant.

Well, proper shellac has been available in the UK for many years. It's more a question of what the particular colouring and density is like with any particular brand. Stuff like the Zinsser will likely be made with a consistent colouring in mind so that it's a known quantity (they'll make it in batches and test/adjust it).

Note that I haven't used the Bird Brand stuff, but I'm tempted to think that it's functionally the same as any other conventional shellac, but it's advisable to test it for colouring and darkness first. Most of the articles I've seen on tarting up a modern tweed amp suggest diluting the first coat 50/50 with more spirit, probably as a way of applying a thin sealer coat to start with and to make the second coat go on more evenly (although that depends on how absorbent the original surface is). That's what I did with the guitar case, and it hardly darkened at all. Based on that, the first coat on the amp was neat from the tin, and it was noticeably darker than the guitar case after that one coat. I stopped at two coats because it was as dark as I wanted it to be.

In short, it's not rocket science. Just get a bottle of the Bird shellac and some bio-ethanol, and try a bit neat on a scrap to gauge the darkness, then either use it neat, or dilute it a bit a try again until you get a dilution that gives the finish you want.