DIY 12v compressor

[Model Mate]

DIY compressor

 

Living on a boat is a wonderful lifestyle but it does come with certain challenges. My lovely Silair compressor unfortunately refuses to operate on my dirty and weedy 240V power supply, so I needed to come up with an alternative.

 

I had a cheap 12V car tyre compressor (and plentiful 12V power) but realised that it wouldn’t give a smooth supply of air, so I needed a reservoir. Last summer I lashed up a terrifying monstrosity using a 5 litre water bottle, aforementioned compressor and the regulating valve and moisture trap from the Silair.

 

This worked surprisingly well, and allowed me to spray a couple of models, but having languished on the boat unattended for too long, started to leak, so I decided it was time for an upgrade.

I found a timber sprayer in Aldi for a tenner and couldn’t resist.

 

Boat life has made me rather “greener” than ever, and the prospect of being able to airbrush without relying on electricity at all was irresistible – despite the fact that my electricity all comes from solar anyway. That said, I decided to connect the 12V compressor regardless, just to have the choice you understand.

 

The timber sprayer comes equipped with two threaded in/outlets. I cut the threaded head off one and inserted a tubeless tyre valve stem with a couple of rubber washers and a good dose of araldite epoxy glue. The mini-compressor’s hose just clips onto this as it would a tyre.

 

The second in/outlet was threaded using a ¼” BSP thread tap. I got a ¼” BSP 45 degree angle, bulkhead fitting and a bunch of male/male and female/female connectors from eBay. I wasn’t sure what exactly would physically fit and couldn’t decide on the orientation, so I thought I’d best cover a few bases. Having the 45 degree angle gave me a bit of flexibility as to whether I want to lie the whole contraption on its side, or have it standing upright. Again using araldite as a thread lock/sealant, I screwed it all together and in.

 

 

BE WARNED – in classically perverse imperial style, a BSP thread that measures ½” is NOT a ½” – it’s actually ¼”! Also, there are DIFFERENT ‘standard’ BSP threads; parallel and tapered – I think we need parallel for this stuff. Honestly, it’s no wonder the British Empire collapsed…

 

The funnel/cup arrangement was cut down as it was a bit cumbersome and the plunger mechanism was reinstated for manual power.

The valve and moisture trap was fitted and the whole contraption was screwed down onto a piece of MDF as a baseplate.

 

It seems to work really well - 30psi in the bottle lasts for a few minutes when you’re only drawing 5-10psi from the airbrush. Once it drops too low, switch on the compressor for a couple of minutes or pump the handle half a dozen times and you’re back up to pressure!

 

I used a few bits and bobs I already had to hand for this, but if you needed to buy everything in, here’s a rough guide:

 

Timber sprayer                                                 £10

12V compressor                                               £15

Pressure regulator & moisture trap                  £10

Pipe fittings                                                     £10

Tubeless tyre valve stem                                  £5

¼” BSP parallel thread tap                               £5

 

So for about £55 (or £35 for a fully manual version) you can have a go-anywhere airbrush setup! No more miserable caravanning holidays!

 

 

 

[Model Mate]

I should have mentioned; if you'd like to see how it performs, have alook at the tail end of my current WIP...

 

 

[stevehnz]

I like the look of that, you've got me thinking now.

Steve.

[Steve Noble]

Is it safe to have a plastic bottle as the air tank?