Metalizing VS TIG welding

[Wiseco]

Hi,

At our company, we mold plastics containers. We also make our molds as we have our own tooling shop.

Now we have one of our mold that is used, it have 10 years of production, many millions bottles made... We have bought a flame metallizing gun in the past that we've never used. I decide to give it a try to repair the mold and remachining it. As the mold only tend to flash at a precise location in the mold, I don't have to rebuild the complete cavity. Now I got 2 cavity rebuild with this process and I must say it does the job so well!!

We have ever tryed to rebuild a cavity with TIG welding but it always leave welding marks which is reflected on the plastics product.

So I'm here asking for some more informations, comparaison on both welding method. Ok... metalizing it's not really welding but hey, you understand what I mean.

My first questions would be : does anyone use metallizing and for what? And why metallizing seam to not be popular in mold repair process?

I would try to take pics to show the before and after of a rebuild cavity.

[Geof]

Many years ago I worked in a shop that used metalizing for building up worn shafts for remachining. I recall that it seemed successful but really it was not. You could build up quite a good thickness and then turn it back to size sometimes finishing off with grinding. The problem was that it was not durable; these were big shafts from mine and mill equipment and very heavily loaded. The metalizing did not seem to get a good enough bond and would flake off under the bearings. I think it might be possible you will get a similar effect in molds. Maybe not in your case because you are dealing with blow molds not injection molds so your clamping forces are not as high.

[Wiseco]

I'm in injection-blow molding and the mold that I metallized is the injection cavities. And the section where I metallized is the contact between the thread ring (which limit the weight of the thread finish and where the cavities is filled last) and the cavity.

By now, I'll try metallizing them without taking away some material before metallizing to see if it bond good to the cavity. If not, I'll simply machined away some of the damage area which will leave a thicker metallizing material to be machined. By now, it only leave 0.0025"-0.005" of metallizing material after being machined so maybe it will flake like you say, but as it support a static load by the clamping force, I think it will not flake as it would with a rotating load like a bearing seat on a shaft.

[RICHARD ZASTROW]

Wiseco
My experience was in the paper industry and similar to Geof's. There are many different alloys available and you must use the best possible match to the base metal. Is yours a powder type like Eutectic or the wire feed type?
My last experience was the wire feed and worked fine replacing the edges on Yankee dryers.

[Wiseco]

Mine is a hot fusion powder metallizing gun.

[RICHARD ZASTROW]

Wiseco
Either process should work. An important caution applies to both: Make absolutely sure you keep the machined area free from any & all oil, coolant, grease, finger prints, fly **** or any other polutants. Keep air supply free of oil and dry. Should work.