That's fine if you want to add shims and increase pressure, but what if you need to lessen the pressure? By your method, you'd still need the original shim in there.... the blade pieces are used behind the hardened shim.
I bought a new 4" gauge off Ebay. It doesn't read in bar, but it'll be fine for as frequently as it'll be used.
Pressure Range: 0 to 3000 PSI
Case Diameter Size: 4" (100mm)
Case Depth: 2”
Connection: 316 SS, welded 1/2" NPT lower mount + ¼” F threaded Snubber insert
Accuracy: ± 1% of span (4A ASME (ANSI) standard B40.1)
Minimum Graduation: 30 PSI
Wetted Parts: 316 Stainless Steel
Case: 316 Stainless with removable front bezel, field fillable (shipped W/O glycerin)
Window: Polycarbonate
Case-to-Socket: Welded
Dial: White aluminum
Pointer: Black aluminum
Media Temperature: 212º F maximum
Ambient Temperature: 30º F to 160º F
I don't know who Weston/Solar is, but for the $15 shipped that I spent for a welded, graded gauge, I'm sure I did pretty well. Most of the gauges I saw weren't graded, or were +/- 3/2/3%.
I'll need to drop a few dollars on some glycerin, but I'm still under $20. I did see mineral oil and silicone oil are used as substitutes, and the seller told me that I could use olive, canola, or any clear, light machine oil.
-Todd