Verdict
Mayco Fundamentals Underglaze is the line most people mean when they say "Mayco underglaze." It is a good choice if you want a wide range of exact shades that work at low fire and mid fire, and you are happy to brush three coats for solid color. Mayco rates the line from cone 06 to cone 10, lists wet clay, greenware and cone 04 bisque as surfaces, and labels it dinnerware safe when a clear glaze goes on top.
The weak points are practical. One coat is not opaque, the jar size changed between catalogs, a dealer copy of the label says not to spray it, and some colors deepen at cone 6 while a few fade at cone 10. This review is research-based: we compared Mayco's product pages, its fired color guide, its 2023 underglaze catalog and US dealer listings, checked October 2026. We did not fire the colors ourselves.
Mayco Fundamentals specs
| Spec | Mayco Fundamentals | Source |
|---|---|---|
| Product type | Underglaze, matte when unglazed | Mayco catalog |
| Cone range | 06 to 10 | Mayco 2023 catalog |
| Fired chips | Cone 06 oxidation on white earthenware; cone 6 oxidation and cone 10 reduction on white stoneware | Mayco color guide |
| Surfaces | Wet or leather-hard clay, greenware, cone 04 bisque | Mayco catalog; label text at Krueger |
| Coats | 3 for opacity; fewer for design | Label text at Krueger and Clay-King (not on Mayco product pages) |
| Finish | Soft matte bare; gloss under clear | Mayco catalog |
| Labels | AP Certified Non-Toxic; dinnerware safe with clear glaze | Mayco catalog; ACMI seal on product pages |
| Colors | 61 | Mayco 2023 catalog |
| Sizes | 4 oz jar and pint; gallon for UG-50 and UG-51 | Mayco product pages |
| Spraying | "Do not spray apply" | Krueger listing |
Source conflict on jar size: Mayco's 2023 catalog lists 2 oz and 16 oz jars, with gallons only for UG-51 China White and UG-50 Jet Black. Mayco's current product pages list a 4 oz jar and a pint, with a gallon for those same two colors. Some sellers still show 2 oz listings, so check the ounces before comparing prices.
What the Fundamentals line is
Fundamentals is Mayco's main underglaze range, sold under UG numbers such as UG-50 Jet Black and UG-72 Wedgewood Blue. Mayco's kit page notes that underglazes were the first product line the company made, in 1954. Mayco says the current line was developed by its ceramic engineer and tested by staff artists for color consistency and performance on different clay bodies and firing temperatures.
The 2023 catalog lists 61 colors: whites and ivories, yellows, oranges, reds, pinks, purples, blues, teals, greens, browns, three grays and Jet Black. That is a larger palette than most home potters need, so you can usually buy the exact shade instead of mixing it. Clay-King's listing adds that the colors can be blended with each other.
Fundamentals is not the same as Mayco's glazes. Stroke & Coat brushes like an underglaze but is a glaze that fires glossy on its own; see our Stroke & Coat review. Mayco's Designer Liner is a clay-based underglaze in a writer-tip bottle for lines and lettering. For every Mayco line in one place, read our Mayco glazes review.
Coats and opacity
Fundamentals is not opaque in one coat. Mayco's product pages do not print a coat count, but the label text reproduced by Krueger Pottery says "Apply 3 coats for opacity; fewer for design," and Clay-King's listing says to use one coat for brushwork and design and three coats for opacity.
One coat gives a soft, slightly see-through layer where brush marks show. That suits line work, shading and washes. Two coats even out most colors, and the third gives the flat, solid color you see in Mayco's chips. Pale colors such as China White, Ivory and Soft Yellow over a darker clay are where a test tile matters most.
- Shake the jar well, as the label directs, and put a little on a tile instead of working from the jar.
- On bisque, wipe the surface with a moistened sponge; the label says lightly dampening the ware helps adhesion.
- Brush the first coat thin and even with a soft brush.
- Let it lose its shine, then brush the second coat in the other direction.
- Add a third coat the same way for solid color.
Our guide on how to use underglaze covers brushes, washes and other techniques in more detail.
Firing range: cone 06, cone 6 and cone 10
Mayco rates Fundamentals from cone 06 to cone 10 and shows every color fired three ways: cone 06 in oxidation on white earthenware, cone 6 in oxidation on white stoneware, and cone 10 in reduction on white stoneware. On Orton's chart for self-supporting cones at 108°F per hour, those are about 1,828°F (998°C), 2,232°F (1,222°C) and 2,345°F (1,285°C). Our pottery cone chart has the full table.
Each product page adds a note for each cone. Here is the pattern from the colors we checked:
| Color | Cone 06 | Cone 6 oxidation | Cone 10 reduction |
|---|---|---|---|
| UG-50 Jet Black | Matte without clear | No change | No change |
| UG-51 China White | Matte without clear | No change | No change |
| UG-72 Wedgewood Blue | Matte without clear | Color concentration | Color fades |
| UG-208 Dragon Red | Matte without clear | Color concentration | Color concentration |
| UG-146 Pink Pink | Matte without clear | Color concentration | Color concentration |
"Color concentration" means the color gets deeper, so a mid-fire potter should pick shades from the cone 6 chip, not the cone 06 one. Clay-King's listing makes the same point when it says some colors shift slightly at cone 6.
Mayco also gives a low-fire tip in its catalog: if cone 06 does not develop the color you want, go hotter, to cone 03 or 04. That suits anyone who paints greenware and bisque fires to cone 04.
Clay stage and application
Mayco's catalog lists two routes. You can apply Fundamentals to wet or leather-hard clay, or to greenware, and fire to cone 04; the catalog says that even on red clay the colors keep their vibrancy. Or you can paint cone 04 bisque. Either way, clear glaze is optional on decorative ware and needed for dinnerware.
The greenware route suits sgraffito: brush three coats at leather hard, carve through, then bisque fire. Our sgraffito guide covers timing and tools. The bisque route is easier for beginners because the pot is stronger and mistakes wash off before firing.
Krueger's copy of the label says "Do not spray apply." Mayco's own product pages do not mention spraying either way, so ask Mayco's technical team before you airbrush. Mayco's 2023 catalog lists Duncan E-Z Stroke Translucent Underglazes for brushwork, airbrushing and antiquing, which is the option to look at if spraying is your method.
Light clay, dark clay
Mayco's fired chips are on white earthenware and white stoneware, so they show each color at its brightest. On buff, speckled or red clay, pale colors lose some brightness unless the coats are full, and the clay can show through thin spots. Mayco's catalog says the colors keep their vibrancy on red clay, but its chips do not show red clay. A base of UG-51 China White under pale colors is one way to brighten them on a dark body; test it on your own clay before a batch.
Clear glaze, food surfaces and labels
Unglazed, Fundamentals fires to a soft matte surface that is fine for decorative pieces. For gloss or a food surface, Mayco says to apply a clear or matte clear glaze. Its product pages recommend SW-001 Stoneware Clear at cone 6 and cone 10, and the color guide shows S-2101 Crystal Clear Brushing over cone 06 chips and SW-004 Zinc-Free Clear over some greens and grays. Check SW-001 Stoneware Clear on Amazon.
Mayco's 2023 catalog says Fundamentals underglazes are "AP Certified Non-Toxic and dinnerware safe when clear glaze is applied," and the product pages carry the ACMI seal and a dinnerware safe badge. That is a label on the materials, not a promise about a finished pot.
We can't promise any glaze combination is food safe on your pots. The dinnerware label depends on a suitable clear glaze fired to its stated cone on a compatible clay body, with no crazing. Read Mayco's Safety Data Sheet for each color, and test finished ware that will hold food. Our food safe glaze guide explains the labels.
Sizes, kits and price
Current Mayco product pages list a 4 oz jar and a pint for most colors, plus a gallon for UG-50 Jet Black and UG-51 China White. The US dealers we checked price the 4 oz jar at about $6 to $8 and the pint at about $19 to $24 in October 2026; check the live price.
The UG-KIT1 Underglaze Assortment Kit is the easy way in. Mayco's kit page lists twelve 4 oz jars: China White, Bright Yellow, Orange, Fire Engine Red, Dragon Red, Regal Purple, Bright Blue, Kings Blue, Apple Green, Leaf Green, Chocolate and Jet Black. With a white and a black included, you can mix tints and shades. The 2023 catalog also lists a pint kit (UG-KT1P) and class packs, and it described UG-KIT1 as 2 oz jars, so check which version a seller has.
What Mayco Fundamentals does well
- Palette: 61 colors in the 2023 catalog, so matching a shade rarely means mixing.
- Fired guide: every color shown at cone 06, 6 and 10, with notes on what changes.
- Flexible timing: wet clay, leather hard, greenware or cone 04 bisque.
- One jar for low and mid fire: black, white and many colors hold at cone 6.
- Labels: AP Certified Non-Toxic, and dinnerware safe with clear per Mayco.
- Jar size: current 4 oz jars hold twice what a 2 oz starter jar does.
Weak points
- Not one-coat: three coats on a large piece takes time.
- Color shifts: reds, pinks and blues deepen at cone 6, and Wedgewood Blue fades at cone 10 reduction.
- No spraying: per the dealer copy of the label.
- Confusing sizes: 2 oz and 4 oz listings both circulate.
- Needs a clear: for gloss and for food surfaces, so it is not a one-step finish.
Who should buy it, and who should skip it
Buy it if you fire anywhere from cone 06 to cone 6, want lots of exact shades, like to decorate both greenware and bisque, and already use a Mayco clear such as SW-001.
Who should skip it: potters who airbrush (the label copy says not to spray), anyone who wants glossy color in one step (Stroke & Coat does that), and cone 10 reduction potters who rely on blues, who should check each color's cone 10 note first.
Alternatives to Mayco Fundamentals
- AMACO Velvet: cone 05 to 10, a velvety matte surface, and three coats for solid color. See our AMACO Velvet review. Check AMACO Velvet on Amazon
- AMACO LUG: AMACO's liquid underglaze, made for covering large areas and listed for sgraffito.
- Speedball Underglaze: cone 05 to 10, 48 colors, with a 12-color sampler of 2 oz bottles.
- Duncan Cover-Coat: an opaque underglaze rated cone 06 to 6.
- Coyote High Fire Underglaze: made for cone 5 to 10 stoneware.
All five are compared side by side in our best underglazes guide.
Sources: Mayco Fundamentals Underglazes fired color guide; Mayco product pages UG-50 Jet Black, UG-51 China White, UG-72 Wedgewood Blue, UG-146 Pink Pink and UG-208 Dragon Red; Mayco UG-KIT1 Underglaze Assortment Kit page; Mayco 2023 Underglazes catalog (dealer-hosted PDF); Mayco 2020 Fundamentals brochure (dealer-hosted PDF); dealer listings at Krueger Pottery (UG-050) and Clay-King (UG-030); Orton cone temperature chart. Specs checked October 2026.