Printable View
Having spent all week preparing primed parts, I got brave today and applied some top coat...
My first attempts were something only Bryant and May would be proud of :o
Once I'd figured out that the HVLP gun will only spray water thin paint things improved. (although I notice i've missed a couple of places so a second coat will be needed)
Tomorrow I plan to tackle the stand and if that goes well the tray and bed.
Why is there a line all the way around the hand wheel in the last pic? You know where there is no paint.
Yes. I didn't mask the polished rim so, before the paint was hard (so it wouldn't chip), I scraped off around the raised edge. I'll clean the over-spray off the rim with emery.Quote:
Originally Posted by Lee Roberts
Well the first coat is done.
Took me a half hour to sweep and hoover the garage floor and generally get ready. another half hour faffing around trying to get the paint the right consistancy so it would make it out of the gun without spitting & blobbing (basically, as runny as water). Surprisingly, I've only one small run (on the back, where I couldn't get far enough away from the stand to spray it properly), if anything I'm still not putting enough paint on.
I'll have to get another litre of paint Monday ready for a second coat sometime next week.
I got mixed result from my second attempt... :(
The small door has come up really well (I'd only given it a quick coat before I'd run out of paint). The second coat on the head and bed are fine . The stand is OK
However. The electrical door, tail stock and power feed box have all pickled into a crinkle finish and parts of the table have also a hint of it.
I'm not really sure why; perhaps the underlying paint was not properly dry, perhaps it was on too thick. :confused:
I'll live with the table top, but I'll have to wait for the paint to harden before I can rub-down and re-spray the other bits.
I'll take some pictures of the head/bed tomorrow. Meanwhile, here's a picture of the reassembled carriage handle. (that odd blue line is a trick of the light - it's actually a very faint scratch that will easily polish out)
Ah yes...my favorite paint style :rolleyes: (since I restore WWII aircraft radios which are almost universally finished in black wrinkle paint.) The wrinkle is caused by statistically random uneven paint film contraction between coats during the curing process. The wrinkle or crackle paints of the 1930s and 1940s were actually produced with additives and techniques that promoted the process between coats.Quote:
Originally Posted by BillTodd
More to the point in your case, there are at least four elements I can recall that contribute to unintentional wrinkling:
1) too much paint film thickness in each coat (partially related to #3 below)
2) incompatible solvents or paint formulations between coats
3) incomplete curing (evaporation of solvents or crosslinking, depending on paint material) of a previous coat before a second coat is applied
and
4) temperature high enough to accelerate problems 1 through 3
What that means in a practical sense is to make sure the solvents of multiple coats are compatible (e.g., water based and oil based following coats are not a good idea, though they often work fine if enough time is allowed between coats), wait long enough between coats, avoid drying heat lamps unless you are sure of the other factors, and keep the film thickness reasonably thin.
It seems sorta ironic thinking about the reverse of the finishes I try to achieve, but the basic principles are fundamental to both results.:)
-Mike
Hi Mike,
Yep, I think no3 is the cause of my problems (and maybe a little No1 - It was surprisingly easy to go from too little paint to too much with just flick of the fan control)
The stand/bed and headstock are OK (I can live with them). I'll redo the the tailstock, electrical door and power feed box later when it's had plenty of time to dry.
I spent this morning bolting a few bits back on (just to make my self feel better about it) I'm happy again :)
Thanks. It seems to have taken an age to ge this far.Quote:
Originally Posted by skittles
Just two :) The other is, I've just discovered, a 9 " Southbend 415-Y automotive special (i.e. it's red instead of grey)Quote:
As a matter of interest, how many lathes do you currently own? :D
[edit] The 415 was cast on 6 Jan 1937 http://www.practicalmachinist.com/vb...&postcount=589
wow, machine looks so nice, great job bill.
Yesterday, after moaning about the lack of industry in Colchester, I found a firm who can metal-spray my carriage gear that is, literally, a stone's throw away from me (well, a stone's throw with a good arm and a fair wind).
I thought Colchester Rewind and Repair just fixed electric motors, but they have a whole range of medium-heavy engineering equipment - You know you're onto a winner when you walk in the door and get; "Hello, I know you. You're Andy's mate; You fixed my computer..."
After talking to Paul, their spraying expert, we agreed that even their hardest power would not be suitable for a needle roller, so I chose to go with the hard power and to make bronze bushes to support the sprayed gear.
Today. I Spent most of the morning waiting for a phone call from CR+R only to find Virgin's phone/Internet & TV were all down :( I popped 'round the corner after lunch and picked up the newly sprayed gear :)
The little Southbend made light work of a couple of bronze bushes (it really is a good little lathe); I decided to put a seal on the rack side of the carriage bearing. I struggled a bit to make the O-ring groove; didn't have a suitable tool, but managed in the end by grinding the life out of an old boring bar (the groove could have been a little deeper, it's a right ******** to get the gear past the seal without pinging the o-ring out of its seat)
I was expecting to have a major job honing/boring the two bearings parallel (the apron front is pinned to the carriage and there are other gears to keep aligned so it has to be right), however, with nothing more than light honing through the pair of bearing with a brass rod and a tap or two with a rubber mallet, the thing went together a treat :)
I couldn't resist test fitting the carriage onto the bed just to feel how the thing moved --Smooooooth :)