every now and again a fab job rolls around that i'd like to get real nice-looking. you know, that clean factory made look... any tips?
by fab job i mean metal/machining work. cutting welding turning milling drilling tapping. nothing high tech.. around here "strong" is all that really counts.
but try as i might... grinding down welds, using expoxies/putties, multiple coats of expensive paint.. the work always looks "hand made" ... thats not always bad
ground down welds, for example.. if you see them in the right light they look like.. well.. a ground down weld.
any pointers?
i know this might be a vague question but i'm hoping someone somewhere understands.
On the fab side it tends to be a function of serious fixtures to hold things square and flat, clean welding to avoid all the spatter and lousy looking beads, and the right finishing equipment like flap wheels and huge belts sanders.
Remember Nordic Trac? Most of their stuff was welded and sent to the paint line for a pebble grain finish. Some of the more exotic weldments went into a vibratory debur before paint. But their welders might do 60 assemblies an hour getting paid on a piece part basis: the welds were fast and minimal.
My suggestion: Always do a test weld 2" away from the real weld, if the first is bad, don't do the real one. Invest in some decent finishing wheels ie the 3M flap wheels on a decent grinder head, the 1" belt sanders, an automatic tube finisher, etc.
Figure out a decent paint system. Semigloss paint hides many sins (I use the the spray bomb from Rustoleum) but the textured ones are even better. Gloss shows all, flat looks cheap.
Laquer putty from an auto body shop supply hides many other sins. Squeege it on, let it dry 30 minutes, wet sand with a block
tony wrote: (clip) the work always looks "hand made" ... thats not always bad (clip) ^^^^^^^^^^^^^^^ This is just my opinion, but I don't think it is "bad" at all. To me, an object which is carefully hand made, with the recognizable signs of skilled craftsmanship is far more attractive and desirable than a mass produced article. Obviously, some things, which are expected to have the "factory look," such as automobiles and household appliances, will look "odd" if you can see the construction techniques. On the other hand, I like to see fine workmanship on things like, say, a dump truck bed or a camper shell. I like the look of a good weld better than the silky roundness of a ground-off weld.
Maybe that's because I grind most of my welds to conceal my poor workmanship.
i walked through a plant a month ago that makes fabricated store fixtures & furniture - tables, shelves, displays etc. they sell to large retailers across North America and have very stringent quality requirements. basic TIG welding of tubing, all done in jigs so everything is nice and square. There is a separate room for finishing which is mainly devoted to very large belt sanders - like belts that are 3 or 4 feet wide in some cases as i recall. QA rejects and returns to finishing any product that doesn't meet standards. from there they are sent out to be plated or left with brush finish, wrapped and shipped. Pres was lamenting how difficult it is to get good finisher which according to him used to be more common trade. He also said he is very aware of matching welders with tasks, some are good at something's and not others, so experience plays a part.
you could get similar results but not with an angle grinder, you're going to have to go through more pain than that :).
The real answer is that every type of operation will have its own techniques, precision machining obviously being different than fabrication etc. It takes real care and thought to produce great results, in industry or the garage IMO Mike
Dress all the bits that need it, sand, then follow up with a clean & strippet disc. Thermally stress relieve, then sandblast. Paint within 4 hours of blastiing.
If that's too much expense or work, just have at it with the grinders. Use a grinding disk to get the contours right, then follow up with a thinner disk, and a tungsten carbide burr for the parts the grinder cant get at. Beware of metal splinters.
A wire wheel attached to a 4.5 inch grinder can be used to smooth things over.
But, by far the best thing for acheiving the "factory finish" is to clean mill scale BEFORE welding, and make sure your fit up is as good as you can get it. The right fit up requires less welding, and therefore less distortion. If you need to make vee and bevel weld preps, use a ruler and protractor to make them until your eye is trained good enough. If you need to flame cut something, use a motorized cutting carriage. If you are getting profiles brought in, look at getting them laser cut, if appropriate.
The appropriate level of pre heat during welding will help keep things neat and tidy, and help your welds blend in. Learn the _BEST_ setting for whatever process you have to use, as opposed to something "good enough".
What I think, is its not about any one thing, but a lot of little things combined, that add up to a proffessional looking job. As always, your mileage will vary. Sorry for the rant.
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